Mobilism - https://forum.mobilism.org/viewforum.php?f=398
Mods.

4PDA - https://4pda.to/forum/index.php?showforum=212

F-Droid - https://f-droid.org/

APKMirror - https://www.apkmirror.com/

Apps

foobar2000 - https://www.foobar2000.org/android
Music player.

eBoox - Google Play
Reader for EPUBs.

Pocketbook - Google Play
Reader for PDFs and DJVUs.

Home Dictionary - https://github.com/mortalis13/HomeDictionary/releases
Great app for .dsl dictionaries.

Feeder - Google Play
Open source RSS reader.

YouTube Revanced - https://github.com/MentalBlank/YouTube-Revanced/releases
YouTube without ads and Shorts.

Smart AudioBook Player - Mobilism
Good audiobook player.

AntenaPod - Google Play
Open source podcast app.

LibreTorrent - https://github.com/proninyaroslav/libretorrent/releases
Open source Bittorent client.

Firefox - Google Play
Don’t use Google Chrome. Google went full totalitarianism removing uBlock. Firefox Android app can install same extensions as desktop browser. Firefox is the GOAT.