[detaro]

HERE maps has a fairly good reputation (formerly Nokia HERE, now owned by a bunch of German car companies)

Locus/Locus Pro are good for looking at maps, it's nice having half the continent available offline. Depends a bit if OpenStreetMap works well in your area or not, and not much in the way of routing/POI as far as I know.

For public transport, there's transportr and Öffi and probably a bunch of specific ones for different regions - again, coverage depends on where you are.