Actually there is a lot of research involved in this, alot of functionalities are extensions of few cool features of photoshop that people would love to have integrated in Unreal engine, like Gaussian , radial blur , photofilter with luminosity on/off , water color , etc. Once I build my own website , I plan to add combo packs of 3-4 filters for , say 4-9$ , so that user can choose to buy only the ones he will use in his game.