Emi Mariduki's work is beaaaautiful. Mainly using watercolor, she creates vividly colorful and surreal universes in her paintings.
Also a little more info... Good day Sunshine as well as tracks 4, 5 and 6 are self-produced. On the title track, SAWA actually worked with a producer I'm not familiar with named Toshihiko Nishibe. It seems he's done work with a few anime soundtracks. Mysterious Zone was created with Jazzin' Park (who remixed Stars and produced I'm a President.) The Kyu Sakamoto cover I'm not sure on yet, but I believe it's acapella?