Pixel Studio Pro is a pretty popular mobile pixel art app. It supports importing .aseprite files, but because there’s no easy way to reimport Pixel Studio files back into Aseprite (apart from exporting each layer as a seperate png), it really limits PS as a good mobile pair with Aseprite.
Would love to see .PSP and .PSD import support for Aseprite in the future, to make pixel art edits on-the-go much simpler!