Henrah,
Rachmaninoff 16/3 is a good one for RH. It has some really tricky chords, and ofcourse, the fact that they're in the RH makes them all the more difficult. This might be a good piece for you to learn.
Can you play this chord (RH)?
G, B, D, F#, A
How about this one?
B, D, F#, A, C#
SJ