I found Pravda skins and other school’s on

https://madwotbmod.wordpress.com/modding-corner/girls-und-panzer-tanks-mods/

Some of the skins:

Zip Files

Full Version:

http://download2014.mediafire.com/swjmfazx8rzg/p6vb4n4xzmmhbh4/GuP+Skins+1.7.1.zip

Pravda Winter Skins:

http://download1626.mediafire.com/ve2jked4clsg/34vcvqb2d059p2n/%5B3.4%5DWinter+Pravda+GuPxWoTB+Skins.zip