Kotatsu-Redo is a free and open-source manga reader for Android with built-in online content sources. The main goal of the fork is to maintain existing features and sources.

Main Features
Online manga catalogues (with 1200+ 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