Beryllium Arrows have a spindly brittle arrowhead, meant to pierce skin and break off in the body, and has the ability to disable the ability to channel mana and cast magic.
Lithium Arrows absorb magic then explode once it reaches a saturation point...
Mana seeking arrows are made to seek out the strongest source of mana in an area and automatically head in that direction...
Opal arrows are made of, well, sharpened Opal. Opal has the ability to absorb aether from living things with ease....