They have done Love Live ones (mainly Eri/Nozomi), several Splatoon ones (the most nsfw ones are based on the Milk Tea/Lemon Tea Splatfest inklings), and Touhou (Satori X Koishi).
Huh, I'd never heard of Spam onigiri before. Looking it up, it turns out that it's a Hawaiian thing, which would be why they included it here. Cool, you learn something new every day.