Buff some classes like: Musician, milkman, santa, necromancer, milkman, elf and hunter.

Here are some ideas to buff them:

Musician - Make it so the banjo can heal US, the user.

Milkman - Make all liquids on you drain .25% per second, but ONLY for
milkman. This includes stuff like acid and kerosene of course, so you can make us take more damage from that of course.

Santa - Make us spawn elf presents every two minutes that work like the eggslinger. You can make the presents spawn with sizes that will give you:
Small: 1 elf
Medium: 2 elves
Large: 3 elves
which will also have the spawn rates of:
Small: 50%
Medium: 40%
Large: 10%

Necromancer - Give us the ability to store our reincarnated allies, and change it so that we lose 5% percent of our health, and the reincarnation rate to 50% chance.

Elf - Buff the frost grenades. You can buff it by simply making the area of the grenade bigger and more deadly for the enemies. Also make us take less damage from fire.

Hunter - Two choices for this one:

1. Give us TRIPLE damage if we use the crossbow against wolves and werewolves or;
2. Give us double damage with our crossbows against everything.

The devs can edit these stats of course to make it more balanced