If you're looking for a Rebind alternative, Trellis is worth a look. Trellis is an AI-powered information retrieval system that comes with a companion AI called Celeste that offers immediate answers and insights to readers. It also has features like customizable audio versions of files, a universal document management system and social sharing of reading logs, so it's both personal and social for reading and learning.
Another option is Converse. Converse is an AI-powered reading companion that lets you interact with web articles, PDF documents and YouTube videos with TLDRs, detailed summaries and a conversational document chat. It also organizes your library and collections and lets you share socially, which can help you read more efficiently and better understand complex material.
For people who like interactive storytelling, Zora offers an adaptive learning platform that uses interactive storytelling to improve reading comprehension and vocabulary. It lets you create your own characters and explore different genres, and gamification makes learning fun and engaging. It's geared for students who want to learn to read in a new and interesting way.