Fitting the right type of ammo can be the difference between success or failure during PvP and NPC combat. However, always remember that the native resists of your target, as well as any shield or armor hardeners, need to be considered.

Not sure who made this, but here is the Ultimate EVE Ammo Cheatsheet

T1 ammunition is also sold in “faction” varieties, which are found either by killing faction pirates, or buying them from LP stores using loyalty points from missions. They deal increased damage over their T1 counterparts with no performance drawbacks. They are a good deal more expensive, but +15% damage varieties are available in large quantities at affordable prices in Empire. Unlike faction modules or ships, you can find and buy faction ammo directly off of the market. For +15% ammo, current prices are about 800-1200 ISK per round for ammo, or 1M ISK for a frequency crystal. Like T2 crystals, faction frequency crystals degrade with use. See Crystal Damage.

Projectile Ammunition

Hybrid Ammunition

Laser Ammunition

Missile Ammunition