Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.

Highly for iOS - Medium-style highlighting in every app and website. 🖌

Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.

LINER - LINER AI Copilot is currently powered by ChatGPT/GPT-4, Google Search Engine, and information from high-quality highlights of an enormous number of users from all around the world.

Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.

Highlight - "Highlight" physical books through conductive pages 📖✨