1. OpenAI: Uses a combination of natural language processing (NLP) and machine learning algorithms. 2. GPTZero: Analyzes linguistic patterns, syntax, and semantic meaning. 3. Quillbot: Evaluates content structure, language, and writing style. 4. CrossPlag: Checks for plagiarism and AI-generated content. 5. ContentScale: Assesses content quality, readability, and AI detection. 6. ZeorGPT: Uses a proprietary algorithm to detect AI-generated text. 7. CopyLeaks: Detects plagiarism, AI-generated content, and duplicate text. 8. Turnitin: Focuses on academic integrity, detecting plagiarism and AI-generated content. 9. UndetectableAI: Specializes in detecting AI-generated text, using advanced NLP techniques.