the hungarian dances are great pieces (although they can be a bit repetitive at times), especially the original four hands versions which are really fun and quite easy. brahms only transcribed the first 10 for solo piano though. these are generally pretty hard, loads of LH jumps and big chords i recall. if you want grade levels, they vary from probably 6-8+ ABRSM.
imo, they sound best played by an orchestra.