One of the best is Gist AI, a free Chrome extension that uses ChatGPT technology to summarize web pages, YouTube videos and PDFs. You can scrub through YouTube videos to find the parts you're interested in, and you can click "read more" to see the original text. It's great for students or professionals who need to quickly digest a lot of documents.
If you need more language smarts, Glarity can summarize and translate webpage content, Google search results, PDFs and more. With large language models like ChatGPT4 and Claude, Glarity also protects privacy and lets you communicate in multiple languages, so it's a good option if you're dealing with documents from around the world.
Last is Briefy, an AI-based system that generates structured summaries of long documents like YouTube videos, emails and PDFs. It can summarize videos chapter by chapter and summarize email threads, and it's available as a Chrome, Safari and Gmail extension. It's designed to help you read more efficiently and stay productive.