Futon is a free and open source manga reader for Android.

Note: Futon is an unofficial fork of Kotatsu

Main Features:

Online manga catalogs (with 1100+ manga sources)
Search manga by name, genres, and more filters
Favorites organized by user-defined categories
Reading history, bookmarks, and incognito mode support
Download manga and read it offline. Third-party CBZ archives are also supported
Clean and convenient Material You UI, optimized for phones, tablets, and desktop
Standard and Webtoon