Q: When I create a new map, I see only Doom-related game configurations. Where are configurations for other games?
A: Copy "[EngineName]_[Game][MapType].cfg" and "Includes" folder from "[GZDB]\Configurations\Configs for other games\[Game]" to "[GZDoom Builder]\Configurations\".
If you are using Zandronum, you'll also need to copy all files from "[GZDB]\Configurations\Configs for other games\Zandronum Includes\" to the main "Includes" folder ("[GZDB]\Configurations\Includes\") .