5-8 - Yellow/white particle explosion.
17-19 - Same as 5-8.
5 TE_EXPLOSION1
6 TE_EXPLOSION2
7 TE_ROCKET_EXPLOSION
8 TE_GRENADE_EXPLOSION
17 TE_ROCKET_EXPLOSION_WATER
18 TE_GRENADE_EXPLOSION_WATER
There aren't any explosion models/sounds with paintball2, so you just get the particle effects, which probably all look the same.
45 - Smoke puff
45 TE_CHAINFIST_SMOKE
This is the effect I built off of to create the smoke grenades. Originally it was just little particle puffs.
The laser sparks were modified to make bigger splatters for the paint grenades. Everything else should be the same as quake2, though the colors will be different because paintball2 has a different palette.