Tranquilizer, p70 - Urban Arcana, under special Ammunition. Used by Air Rifles and Pistols further up in the equipment section.
Other stuff that might be useful:
Net Launcher - Urban Arcana
Sticky Foam Sprayer - Urban Arcana
Blowgun - Urban Arcana, with poisons from d20 Modern
Specialized Equipment - Dark Matter
some drugs, grenades, and other stuff that can be used.
Pepper Spray, Taser, Stungun - d20 Modern
Different types of grenades: smoke, tear gas, flash-bang, etc.