Bowser gets a full-on, proper painting of him beating up both Mario and Luigi at the same time and looking super-badass doing so.
Emily Fields gets a pen and ink portrait of herself done from memory.
Jennifer Check gets printed maps of various neighborhoods in New York cities with a shit-ton of notes/highlights of stuff she might like/places she might want to shop at.
Ramona Flowers gets tequila and a landscape-ish painting of mountains in winter (done from a perspective where it looks like you're gazing up at them) and chew blocks for her rabbit.
Wendy Watson gets a new side room in the art studio to do with as she sees fit. The really nice couch is staying in the main area but maybe a somewhat less awesome one can be in there.