Arbitrary
Tranny Chaser
Tons of people like chasing the hunter achievements, firsts, and so forth. This would give it an actual reason beyond just people's natural need to collect things for their OCD. It'd make for some interesting guild competitions beyond the usual "rushing to gank spawns".
It checks a very important box too - it's something that Daybreak could actually do with a whole lot of the work already being in place

