I got to see Vic Viper perform live a few months ago at a local retro game convention. They killed it. This group puts on an intense set that has to be seen live to be appreciated. Check out this album which pays tribute to a variety of classic and niche NES sountracks, and also Mega Man 9, which isn't technically for the NES.
Game music collective Pixel Mixers present a tribute to classic 2D Legend of Zelda with the Hylian Downfall compilation