What about semi homing arrows? They home in on enemies for about 3 seconds, then stops homing...
Or maybe Rail Arrows, they hitscan.
A bow variant, ballista, it fires quicker arrows (That can also split when upgraded), but it has a reload time added to it.
Neon Arrows, they stick to the ground and can distract certain enemies, maybe they can electrocute them, removing random Voxels from their body, and paralyzing them.
Explosive Arrows, those explode with the power of about a third of a Spidertron 'nade.
Antigrav Arrows, they make enemies float if they are hit (Mostly useless, because robots don't take fall damage... future update?), or they act like the current arrows...
I also thought about arrows having actual physics, instead of, you know they magically defying gravity (Not magically, although I think those arrows are made of plasma), thus, the Antigrav Arrows would act like the old arrows, and have an actual use other than to laugh at floating robots...
(MK2 Combat Swordsman, after getting hit by Antigrav Arrow) AHHHHH!!! I'M FLYING, WHAT'S GOING ON!? HALP, HALP!!!!!!!!!!!!!! Welp, I'm immune to fall damage anyways..