I can’t believe this name wasn’t already taken.
Aegis: 2fa. Free, open source.
Auto Auto-rotate: per app rotation settings. Free, open source.
Missed notifications reminder: adds a repeating sound or vibration if a watched app has an active notification. Ie, you got an email when you were away from your phone so every few minutes your phone makes a beep or whatever so you don’t need to check the screen constantly. Free, open source.
MJ PDF: simple, fast PDF reader. Free, open source.
Snap drop: web based instant file transfer between devices. Free, open source.
X-Plore: the only file manager that ever clicked for me. Dual pane that’s really intuitive. Absolutely packed with features (connects with local network, cloud providers, ftp, ssh, dlna, has file sync)
I always want my gallery app to rotate. I never want my email app to rotate. Auto-auto-rotate remembers the last rotation setting for every app I use and will turn it on or off for me. After a day of normal use I literally haven’t had to touch the system rotate setting once. It’s fully automatic and took zero effort. Having to change the setting manually is more of a hassle than this.