I love Fotor, Fantasia Painter, InstaBlender and Squarify.
Fantasia Painter has the most options, but to me it's a little all over the place as far as layout. (I probably just need to mess with it more.) I find myself using Fotor the most for it's simplicity and great processing quality. I also love the undo/redo function as well as the ability to do multiple adjustments on brightness, contrast, saturation and sharpening all before you commit to any of them. In Fotor I would like to see a vignetting effect similar to to the 'Center Focus' effect in Snapseed. I would also love if they added a color/temperature balance tool.
Photo Editor by Aviary is nice in design but it lowers the resolution of the photos with no option to save as higher quality.