Guild Wars 2

The idea: get rid of diminishing returns and reward players for spreading out instead:

You have that mob-families (pirates, skelk, ogres,…). Once you kill an enemy of one specific family, all other families gain a bonus of +(random number) 0,5 MF for yourself only. So if you kill 20 pirates, all other families gain +10% MF for you. Other players have their own personal bonus MF on enemy mobs. Maximum amount of bonus MF: +300%

Now you go and kill a ogre. He gained that +10% MF from you killing 20 pirates. For each ogre you kill, ogres lose 0,5% MF until they are on 0 again, while all the other enemies gain MF.

If you haven’t killed Risen for a long time, those will have a pretty huge amount of bonus MF, but lose that again slowly when you start killing those.

TL;DR: killing mob family A increases bonus Magic Find for all other mob families. Killing mob family B after that slowly decreases MF back to norm again, while increasing bMF for the other families.

The idea sounds good, but I could go to a starter area, Queensdale for example, go to troll cave and kill the lots of grubs there. So now every other mob family has idk, 20-30% MF, and then move to another starter area and repeat until I cap MF for other families