58724
Canama: Shooting blasts of energy instead of bullets. Theoretically also reskinning the guns, but that isn't truly needed. However; can you use melee weapons as well?
58725
I have no idea if there's a mod for that, but I have no idea what it would change about the game. You barely see the bullets anyways. Yes, there are melee weapons.
If what you are trying to do is make the game blood free,
there's a mod for that. (I have it installed myself). Be warned that it does not work on VAC-enabled servers with cv_pure set to 1, which unfortunately is a category that includes the vast majority of servers.
-Canama