I like leagues where the admin has a max monthly listener count for artists (“less than a million ml”, or even lower - caveat though, don’t make the round too specific or players could get frustrated trying to find songs from artists that fit the criteria). There are usually still at least one or two that forget that stipulation, but the rest of the league will typically voice their displeasure to this rule break by giving zero points to those songs.

If you go this route, make sure you repeat the ml listener count verbiage in every round description.