OFMA Charts available for free to all basic subscriptions of "Flight Assistant v2.2" (android)

All open flightmaps maps available for free(**)

open flightmaps is a group that creates open source aviation maps.

They are currently covering e few countries, mostly in central and Northern Europe (Germany, Austria, Denmark, Slovenia, Hungary, Switzerland, Romania and Bulgaria very soon), but the coverage increases nicely and regularly.

With a Basic subscription or above, you can use all the maps from open flightmaps free of charge.

And obviously you can still use your own maps if you own any.

**: with a Basic (or above) subscription plan

more info to be found here.