There aren't a lot of nail art techniques I haven't tried, but something I have been meaning to try for a while is a 'jelly stampwich'. Being that in between the layers of the jelly (semi transparent) polish, I stamped some hands.
Base Polish: Color Club - Mrs Robinson
Stamping Polish: W7 - Black
Stamping Plate: MoYou - 72
Base Polish: Color Club - Mrs Robinson
Stamping Polish: W7 - Black
Stamping Plate: MoYou - 72