Some of these might be from other repos, such as IzzyOnDroid

Adaway - systemwide ad blocking (root)

Aegis - authenticator

AntennaPod - podcasts

App Manager - very extensively-featured package manager (root)

Droidify - alternate F-Droid client with QOL features

Endless Sky - game, space trading/combat

Feeder - RSS reader

Gophercle - internet browser for gopher instead of http

Hacki - HackerNews client (for those who can tolerate its userbase)

Jerboa for Lemmy - the only currently-released Lemmy client that is anywhere near feature parity with mobile web

K-9 Mail - email client, will eventually be replaced with Thunderbird

Kotatsu - japanimation mango reader

Librera - eBook and PDF reader

NewPipe x SponsorBlock - NewPipe fork with SponsorBlock

Obtanium - notifies of/auto-downloads new releases of apps on GitHub, etc

OpenBoard - FOSS keyboard, doesn’t play nice with Jerboa due to a long-ignored bug in the AOSP keyboard itself but works perfectly everywhere else

Orgzly - text-based notes and tasks, supports automatic backups to user-defined repos including online or external storage, uses its own weird file format though

ProtonMail - official ProtonMail client

ProtonVPN - official ProtonVPN client

Record You - most painless voice/screen recorder I’ve found

Simple File Manager - self-explanatory

Simple Gallery - same

Tasks.org - easy scheduled reminders with priority tiers, low-tier might not notify you at the night time due to Google ruining how Android does background running

Termux - terminal emulator with QOL packages

Translate You - lightweight offline translation

Unciv - game, clone of Civilization V in its 2D mode, genuinely more fun than the original

URL Radio - internet radio browser/client

Video Transcoder - self-explanatory

VLC - the final word in media players, video files specifically