it's once again differ per person. because music taste is always different.
personally i like music with interesting drop and variates. DnB is excluded they have different technique to make them awesome.
i also love DnB with vocal, like tidal wave or starscrapper. bemani song most of the time has same feel as DnB, but with different flow.
for mapping purpose, anything has different mapping style, and this make the variation between mapper.
the most standard song to map is around 140~180 BPM anime style song like yasashisa no riyuu and the other.
DnB most of the time is too repetitive, this force the mapper to be creative to make something interesting.
SpeedCore isn't always necessary to be mapped, as the purpose of the song is to strain the listener spirit to the max.
there's also some unique music type like glitch, kawaii core, etc. but for general mapping information, those 3 is already fulfill the criteria