This is going to be a long list.

VLC, for playing videos and other media.

Auxio, for playing music and organizing playlists and such.

ConnectBot, for SSH.

Shizuku, for apps that support it.

RootlessJamesDSP, for audio stuff. Powered by Shizuku.

aShell, for stuff that requires root permission.

Aurora Store, for the few apps I need from the playstore.

KISS Launcher.

Droidify, for everything I need from F-Droid. Also powered by Shizuku.

Feeder, for RSS feeds.

FTPClient, for SFTP connections.

LibreTorrent, for torrenting and such.

Mull, for web browsing.