While this is about data of the city of Hamburg, Germany, I decided to post in English as GeoPackage Propaganda should be accessible. ;)
I am casually working on converting open geodata released via the Transparenzportal Hamburg to more usable GeoPackages, GeoTIFFs and similar formats with free and open-source tools like GDAL and GMT where possible. This includes things like orthophotos, ALKIS, addresses, DEM, districts etc. You can get a list of most available source data here but there are some datasets “hidden” in other categories as well. The data is usually released in GML or as gridded files (e.g. JPEG or XYZ tiles/files). While this is pretty much perfect as source formats, working with them is cumbersome. My goal is to make this data more accessible for anyone in tools like QGIS.
For now you can find the 20cm orthophotos for 2013-2015 and the 1m DEM in https://www.datenatlas.de/geodata/public/hamburg/. Mind the licenses, see the readme file for a bit of info. More to come, I want to plan the pipeline a bit better first though. There should be a full script & log from source to GeoPackage for each file.
I will also provide mirrors of the source files. If you want to collaborate, please contact me. Apart from Hamburg I will also add free/open datasets for the whole of Germany, things related to (nearby) bathymetry and some global ones. If you want Shapefiles, ECW, MrSID or similar, you can pay me for converting.