megazb's/shotty's ZaPT zombie survival (or zapt servers in general i guess)
it was just gsf miami with zapt spawns everywhere and some weapon/vehicle spawns, but it was so much fun to 7th grade me
also one of the earlier servers i joined when I first got a key was slightly similar. It was GSF paradise with L4B, zombie dogs, hydralisks, etc all spawning around the map. It was such a huge map that it was actually impressive that there were that many spawns. People would claim buildings and areas as bases and defend them against any bots that spawned nearby, as well as hostile players. I remember I grouped up with some people and a guy was trying to snipe us with the default rocket launcher from super far away. I wish I had the build saved.