Nova launcher (super customizable and clean and you can unlock premium with revanced Manager)

KWGT (allows you to create custom widgets for your phone and has a very good editor so you can jam pack all the info you want into one widget)

Revanced Manager (ad free YouTube with extra features like return dislike and sponsor block and more)

Xmanager (free Spotify premium)

Vlc (best way to play video and audio files)

Fdroid (alternative app store which allows you to basically find a clone of most apps but open source and privacy friendly, plus a ton of other privacy respecting apps)

Aurora store (Google Play store but more customization and less Google tracking stuff attached)

Seal (allows you to download videos and stuff from basically any big site)