As in title, preferably open-source, but doesn’t have to, I will start:

KOReader - Amazing reader app, and being able to use the same app across various devices, even non-android ones, is pure bliss. Japanese support is pretty good too, which makes me happy. Though… Sadly no vertical text support :c

Syncthing-fork - Being able to keep a library of books, and some files, and easily keep the shared folder across various devices, is mega comfy. Tachiyomi - Cute manga reader.

NewPipe - Really pleasant youtube client, that i sometimes use to listen to things in the background.

Kaku - An useful Japanese OCR app, that works… quite decently for when I encounter kanji that I do not recognize, and is not text.

EinkBro - A web browser, that on e-ink devices, is quite comfy. Has few… quirks, but works well on e-ink

    • Florisboard - FOSS keyboard with support for glide typing
    • KISS Launcher - Lightweight, search based, customizable launcher. Also
    • MuPDF - PDF viewer
    • Logseq - Notes. TODO list. Ideas
    • Syncthing - For syncing across devices
    • Newpipe - Youtube clilent
    • K-9 mail - For email
    • Feeder - RSS feeds
    • Tusky - Fediverse
    • Mull browser
    • Brave browser
    • Organic Maps - For maps and navigation.
    • GMaps WV - For maps and navigation.
    • Auxio - music player
    • Bitwarden
    • Termux
    • Mega-android - Cloud storage

    And ofcourse, F-Droid with additional repos (IzzyOnDroid, Newpipe etc.)