An interesting option is "Sentinelsat", an open source Python based tool which makes searching, downloading and retrieving the metadata of Sentinel satellite images from the Copernicus Open Access Hub easy. The Sentinel data are global open data (Radar, optical and thermal data are available).
Software and instructions at https://sentinelsat.readthedocs.io/
These Russia census bureau regional level data on nationalities may be what you need https://www.gks.ru/free_doc/new_site/perepis2010/croc/perepis_itogi1612-tom4.htm
Take p.4 https://www.gks.ru/free_doc/new_site/perepis2010/croc/Documents/Vol4/pub-04-04.xlsx
and there are more data from 2010 population census
I've done work in this space and my recollection is that Ethnologue, George P. Murdock's Standard Cross Cultural Sample, and the Ethnographic Atlas (also by Murdock) were the more commonly used datasets in research requiring georeferenced data. The problem is that Ethnologue is certainly not open and Murdock's datasets are not guaranteed to be up to date. ...
One word answer: Iceland
One sentence answer: Subject to the methodology and caveats below, with an estimated 2020 poulation center latitude of 64.336, Iceland has the northernmost population center among soverign nations, with Finland coming in second at 61.715, and Norway coming in third at 61.049
Using CIESIN gridded population data and ...
A reasonable approach would be to obtain layers of (1) elevation data such as SRTM and (2) natural resources and overlay them.
For (1), see EarthExplorer and look under the section "Digital Elevation". Note that the link you posted is likely your best best for the data in .hgt format. For (2), the U.S. Energy Information Administration has a set of maps ...
Detailed spatial data seems to require a CNDDB subscription.
You could put together quad level data (USGS 7.5 minute topographic quads) with this publicly available endpoint that lets you query what species are in a particular quad.
For example, for quad 3811957: https://apps.wildlife.ca.gov/bios/rest/Cnddb.ashx?o=cnddbQuickView&p=QuadSpecies&q=...
I found KML files for district level boundaries for all UK Postcode areas on github at https://github.com/missinglink/uk-postcode-polygons/tree/master/kml
have tested with one file on google maps and it overlays the boundaries correctly