Δωρεάν Εργαλεία Τεχνητής Νοημοσύνης

Artificial Intelligence (AI) chatbots have become essential tools for content creators, students, professionals, and businesses. From generating content and coding to providing real-time search insights or fun roleplay, today's chatbots are more advanced than ever.

ChatGPT (by OpenAI)

A leading AI conversational assistant that can answer questions, draft text, code, and even generate images.

It has over 400 million weekly active users and ~4.5 billion visits per month. The free tier gives access to the GPT-4o model (via chat.openai.com) with daily usage limits.

Users can create custom GPTs or use text-to-image prompts, while advanced features (voice chat, search, etc.) require the paid ChatGPT Plus subscription.

ChatGPT remains the most-visited AI tool on the internet.

ChatGPT application interface

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Key Features

• Conversational AI with natural human-like responses
• Multimodal (text, image, and code) support
• Integrations with DALL·E, data analysis, and web browsing
• Custom GPTs and plugins for tailored experiences

Pricing

• Free plan: Access to GPT-3.5
• ChatGPT Plus: $20/month for GPT-4 access and faster responses

Best for: Writers, marketers, students, and professionals who need an all-in-one AI assistant.

Google Bard / Gemini (by Google DeepMind)

Google's AI assistant (formerly called Bard) is free to anyone with a Google account. It supports both text and image inputs and integrates with Google Search and Docs.

Google reports Gemini's free version (Gemini Lite) handles creative tasks, summaries, and research with up-to-date knowledge.

G2 notes that Gemini has a 2.47% share of the AI chatbot market – well behind ChatGPT but still popular.

Its tight integration into Google's ecosystem makes Bard/Gemini widely used for casual queries and productivity.

Google Gemini AI interface

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Key Features

• Deep reasoning and multimodal understanding
• Integration with Google Workspace (Docs, Sheets, Gmail)
• Real-time web access for up-to-date information
• Supports coding and math problem solving

Pricing

• Free version: Gemini (basic access)
• Gemini Advanced: Included in Google One AI Premium ($19.99/month)

Best for: Users deeply integrated into Google's ecosystem who need search-enhanced AI.

Claude (by Anthropic)

Claude is a general-purpose AI chat assistant known for safety and longer-form text generation.

Anthropic's Claude offers a free tier (Claude 3 Opus Lite) that lets users chat, brainstorm, or write with an "easy-to-use interface".

It excels at creative and technical tasks while prioritizing user privacy. Claude's free plan is attractive for students and professionals who need a more "responsible" chatbot experience.

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Key Features

• Handles very long context windows (200K+ tokens)
• Great for document analysis, summarization, and logic tasks
• Focused on ethical and safe AI responses
• Available via web or API

Pricing

• Free access on Claude.ai
• Claude Pro: $20/month (priority access & higher limits)

Best for: Researchers, developers, and professionals needing precise, context-aware responses.

Microsoft Bing Chat (Copilot)

Built into the Bing search engine and Microsoft Edge, Bing Chat (Copilot) uses OpenAI's models to provide answers, summaries, and even DALL·E image generation.

It's free for all users with a Microsoft account. Key features include real-time web access (for current information) and integrated workflow with Windows and Office apps.

Because it's web-integrated, Bing Chat is a popular AI assistant for search and productivity tasks.

Microsoft Bing Chat AI interface

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Key Features

• Internet-connected, real-time answers
• Image creation via DALL·E 3
• Seamless integration with Microsoft Office and Outlook
• Can handle creative, educational, and research tasks

Pricing

• Free version available to all users
• Microsoft 365 Copilot: Starts from $30/user/month

Best for: Business professionals and enterprises using Microsoft tools daily.

Perplexity AI

Perplexity is an AI-powered research assistant that combines live web browsing with conversational answers.

Its free tier allows unlimited basic queries and always cites sources. Perplexity is especially useful for fact-checking and research: it returns up-to-date answers with links, making it stand out from generic chatbots.

Users often prefer it when they need accurate, sourced information.

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Key Features

• Provides sourced answers with clickable references
• Uses GPT-4 Turbo and Claude 3 models
• Allows file and image uploads for contextual responses
• Great for summarization and quick learning

Pricing

• Free version with standard features
• Pro Plan: $20/month (unlimited GPT-4 Turbo & faster results)

Best for: Students, journalists, and researchers who value accuracy and citations.

Character.AI

This platform lets users chat with custom "characters" powered by AI (literary figures, celebrities, etc.).

It's free to use (with optional paid upgrades) and has seen explosive growth: as of mid-2024 Character.AI had 20 million monthly active users and over 200 million visits worldwide.

The app is especially popular among young users who enjoy conversational role-play.

Character.AI platform interface

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Key Features

• Create custom AI characters with unique personalities
• Roleplay, group chat, and story generation
• Voice conversations with selected characters
• Mobile app available for Android & iOS

Pricing

• Free access for all users
• Character.AI Plus: $9.99/month (faster responses & early access features)

Best for: Entertainment, roleplay enthusiasts, and creative writers.

INVIAI Free AI Chat

INVIAI Chat AI is a free online GPT chat platform that helps you chat directly with leading AI models such as GPT, Claude, Gemini and Grok.

Users can use it immediately without registration, no credit card required, 24/7 experience with 99.9% stability.

With a friendly interface, fast processing speed and high security, INVIAI's free AI Chat tool supports content creation, answering questions, studying and working effectively.

This is the ideal choice for anyone who wants to exploit the power of AI easily and completely free.

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Key Features

• Access to multiple AI models and chat assistants
• Tools for writing, marketing, and SEO optimization
• AI image and content generation
• Free access with no login barriers

Pricing

• Free plan available with full chat access
• Premium tiers for faster replies and extended features

Best for: Small businesses, content creators, and users seeking a cost-effective all-in-one AI chat tool.

Pricing Comparison Table (2025)

Which AI Chatbot Is Right for You?

Conclusion

AI chatbots are rapidly evolving — from creative writing assistants to professional productivity tools.

• ChatGPT, Claude, and Gemini dominate in reasoning and productivity.
• Perplexity AI leads in research accuracy.
• Character.AI excels in fun, interactive experiences.
• INVIAI provides accessible AI chat for everyone, for free.

No matter your needs — whether it's for learning, content creation, business, or entertainment — there's an AI chatbot designed just for you.

In today's digital workspace, AI-powered writing and productivity tools are essential for professionals, students, and content creators. From improving grammar and translation to summarizing and note-taking, these AIs make communication faster, clearer, and more efficient.

Grammarly

Grammarly is one of the most widely used AI-powered writing assistants that checks grammar, spelling, punctuation, and tone in real time. It's ideal for writers who want to improve clarity and professionalism in their writing.

Grammarly writing assistant interface

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Pros

• Excellent grammar and style correction
• Detects tone and intent automatically
• Integrates with browsers, Word, and email apps

Cons

• Limited creative writing capability
• Premium subscription needed for advanced feedback

Pricing

• Free plan: Basic grammar and spelling check
• Premium: $12/month
• Business plan: $15/user/month

Best for: Students, writers, professionals who need accurate writing corrections.

DeepL

DeepL is one of the most accurate AI translation and writing refinement tools in the world. It provides natural, human-like translations and now includes DeepL Write, which helps improve sentence clarity and flow.

DeepL translation interface

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Pros

• Exceptional translation accuracy
• Supports 30+ languages
• DeepL Write improves sentence fluency

Cons

• Limited language support compared to Google Translate
• Lacks advanced grammar feedback like Grammarly

Pricing

• Free plan: Basic translation
• Pro plan: From $10.49/month
• Team/Enterprise plans: Custom pricing

Best for: Multilingual professionals, translators, and global content creators.

QuillBot

QuillBot is an AI-based paraphrasing and grammar-checking tool designed to improve sentence variety, readability, and style. It's widely used by students, researchers, and content writers for rewriting and summarizing text.

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Pros

• Excellent paraphrasing & summarizing tools
• Grammar checker and citation generator included
• Easy-to-use Chrome and Word integrations

Cons

• Free plan has limited rephrasing modes
• Occasional context inaccuracies in complex sentences

Pricing

• Free plan: Basic paraphrasing (2 modes)
• Premium: $8.33/month (billed annually)

Best for: Students, academic writers, and bloggers seeking rewording support.

Otter.ai

Otter.ai is a leading AI transcription and meeting productivity tool that automatically converts speech to text. It's ideal for meetings, interviews, and lectures — allowing you to focus on discussions while Otter handles note-taking.

Otter AI transcription interface

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Pros

• Real-time transcription with high accuracy
• Integrates with Zoom, Google Meet, and MS Teams
• Auto speaker identification and summaries

Cons

• Limited offline functionality
• Transcription accuracy may vary with accents

Pricing

• Free plan: 300 monthly transcription minutes
• Pro plan: $16.99/month
• Business plan: $30/month

Best for: Professionals, journalists, and students recording meetings or lectures.

Pricing & Features Comparison

Pros and Cons Summary

Which AI Tool Should You Choose?

Final Thoughts

Each of these Writing and Productivity AI tools serves a unique purpose:

• Grammarly ensures error-free, clear writing.
• DeepL enables seamless multilingual communication.
• QuillBot helps you rephrase and summarize effectively.
• Otter.ai boosts meeting productivity with automated transcription.

Whether you're writing an article, translating text, or capturing meeting notes, these AIs are essential tools to enhance your daily workflow.

Visual creativity has its own set of free AI tools. DALL·E 3 (OpenAI) is an AI image generator accessible through ChatGPT: simply describe your idea and ChatGPT will automatically generate tailored, detailed prompts for DALL·E 3 to create the image. The images you create are yours to use freely.

Another major tool is Stable Diffusion, an open-source model for generating and editing images from text. Stable Diffusion powers many free web interfaces and apps (and can even run locally) – it's designed to generate high-quality, detailed images from text descriptions. Social media creators often use Stable Diffusion via sites like DreamStudio (which offers free credits) or via community tools.

Design platforms have also embraced AI. Canva's Magic Studio bundles dozens of free AI features (Magic Write, Magic Design, Magic Media, etc.) for images, text, and video.

Canva reports that its AI tools have been used more than 10 billion times to date, illustrating its popularity. Many Magic Studio features are available on Canva's free plan (for example, Magic Write offers 25 free generations per month).

Adobe Firefly similarly offers free image, vector, and video generation tools for creators with an Adobe account. These AI design tools let anyone generate social-media graphics, marketing images, or art with simple text prompts – all without paying for extra software.

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Several free AI tools streamline audio and video production workflows. Runway offers a free tier with limited credits for AI-powered video editing—generate short video clips or apply visual effects using text or image prompts.

For audio production, ElevenLabs provides a free trial of advanced AI voice synthesis, including voice cloning and text-to-speech capabilities. Otter.ai offers a free plan for automated meeting transcription.

Murf.ai and Descript also feature limited free tiers for AI voiceovers, enabling users to create podcasts, voiceovers, or video content without upfront costs beyond registration.

For efficient meeting management, Fathom serves as a free AI notetaker that records and summarizes Zoom or Google Meet calls—eliminating manual note-taking.

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