openaip
https://gpsjam.org/
Maps of likely GPS interference, based on aircraft reports of their navigation system accuracy.
https://notaminfo.com/international
Aeronautical chart from OPENAIP
openflightmaps aeronautical chart
SkyVector - Aeronautical Charts
Opentopomap
Openrailwaymap
Openseamap
Openstreetmap
Google Airports D A CH
Forest chart from DLR
https://www.ead.eurocontrol.int
NOP - Network Operations Portal
Flight information region (FIR/UIR) charts - 2022
Austria
Belgium
Bosnia and Herzegowina
Bulgaria
Croatia
Czech Republic
Denmark
Estonia
Finland
France
Germany
Greece
Hungary
Iceland
Ireland
Italy
Latvia
Lithuania
Luxembourg
Moldava
Montenegro
Netherlands
Northmacedonia
Norway
Poland
Portugal
Romania
Slovak Republic
Slovenia
Spain
Sweden
Turkey
United Kingdom