I know a few people already posted some stuff on this, but they're not very organized and detailed, so here we go!
Seriously, we need more gamemodes! TDM, Elimination, Soccer, that's it? Boring.
Gamemodes:
Free For All
There are spawnpoints spread around the map, it's everyone for themselves. The score count at the top next to the timer would be modified so that it shows your kills instead of Blue kills vs Red kills.
For compatibility, add the ability to place separate FFA spawnpoints for custom maps (not sure how that will work for only sniper maps lol).
Win: highest kills
Capture the Flag
A flag is placed at spawn. Your goal is to enter your enemy's spawn and take the flag. Then, you need to get back to your own base, and reach your own spawn (this will add 1 point to the score counter). You can also kill an enemy who has your flag, which will make them drop their flag, making them start over. The flag is then returned to your base. If you get the flag back to your base, you get 20 xp.
Flags will appear at the spawnpoint. Players who have enemy's flag will have a little flag icon floating above them, visible to all players. The location will also be visible on the radar. For maps with multiple spawnpoints, the flag will randomly choose one of them as the location. (playing ctf will be a bad idea on maps like Snow War 2019 lol)
Win: first to get 10 flags on team
Tag
Very similar to TDM, but if you kill an enemy, they will respawn on your team. Team balancing will be disabled for this gamemode.
Win: all players on own team
Infection
Also very similar to TDM, but everyone except for one player spawns on blue. The one red player has to kill blue players. Upon death, blue players become red (no death, you just magically switch teams). Blue players are normal, red players are zombies. Zombies can't use Hummer, Jets, Armory, or weapons. They also have slower speed (like using mini g walking speed) and they can't sprint. However, zombies can't be killed (they have infinite health), and they can one hit "kill" by punching. Also no team balancing for this gamemode.