If you ever played Sudden Strike you would be happy to see some free stand alone mods for it. Modern Warfare Mod 3 and Vietnam Project are 2 of the best mods i have seen for a game. You could call them total conversions and the best part is you do NOT need the base game in order to play.

https://www.sudden-strike-maps.de/phpBB2/viewtopic.php?f=159&t=19287

https://translate.google.com.au/translate?hl=en&sl=de&u=https://www.sudden-strike-maps.de/index.php/downloads/download/34-vietnam-project-software/322-vietnam-project-v-1-2&prev=search

http://sudden-strike.net