I prefer Gaia to both OnX and Basemap. Same functionality or better across the board IMO. Carplay integration is nice at times when running forest roads or looking for road-based waypoints from the truck, and they're back to working on Android Auto. Number of layers is pretty astounding. With that said, I've been considering giving OnX a go again because they're including memberships to TopRut and Huntin Fool for free.
Other Apps:
iExit for road trips - pretty indispensable
MyRadar for weather Radar
LunaSolCal for sunrise / sunset
Windy for Wind
Weather I've been going back and forth, currently Today Weather, Hyperlocal Weather, and Climacell. Some use Dark Sky as their source
Garmin Inreach App
Garmin Connect for my other Garmin Devices
Strava for training / etc.
Kestrel App, Kilo 2400 App, Autotrickler App, Ballistic X for tracking group size at the range