Icemario
Lady Lyndis
Towns Folk
SSB 3DS has the most vivid memories, so I stick to that.
Wario Ware Inc. because of its ridiculous microgame system (specifically the reward part of it), Balloon Fight because it's too small and easy to get cheap KOs on it, Jungle Japes because of the rapids, and to a lesser extent Green Hill Zone because the breaking ground and close edges are both bothers.
Maybe more but this is what comes to mind.
Wario Ware Inc. because of its ridiculous microgame system (specifically the reward part of it), Balloon Fight because it's too small and easy to get cheap KOs on it, Jungle Japes because of the rapids, and to a lesser extent Green Hill Zone because the breaking ground and close edges are both bothers.
Maybe more but this is what comes to mind.