a few days ago i set my phone up with a lineage without opengapps, and used microg instead. without the playstore and google services, i needed some replacements.
a list.
alternative stores
- app store with free and open source apps
 
- access to free apps in the play store (available in f-droid)
 
maps
- openstreetmap client; works offline!
 
- public transport app with lots of backends!
 
- find vegetarian and vegan restaurants, based on openstreetmap
 
weather
- a nice and simple weather app; uses openweathermap. includes widgets!
 
- a surprisingly usable mail app
 
calendar
- nice calendar app
 
- sync caldav calendars to your phone
 
messaging
- secure messaging. if you want people to switch away from whatsapp, this is probably what comes closest.
 
- a nice xmpp client
 
- a fediverse client; free in f-droid!
 
security
- filter ads across all your apps!
 
apps to support free databases
- nice app to fill some of the gaps in openstreetmap. just answer simple questions.
 
- help make mozillas location service better
 
- get foodfacts by scanning barcodes on products. also, help fill the database!