"1 AM" from Animal Crossing: New Leaf is a very simplistic and calming piece built around a piano.
"Onaji hoshi ni Umarete" from Hoshizora no Memoria sounds like space opera music because it matches classical sounds with electronic sounds. It is graceful yet still upbeat.
"Path to Lucy" by Deaf Center is a serene mix of the orchestral and the ambient, creating a strong sense of atmosphere.
"Rockin the Suburbs" by Ben Folds is basically a fun song about being male, middle class, and white that mocks angry white guy music. Yes, it is power pop.