I think something like #handmade, which is used for crafts and such, would fit best. I reckon #HandmadeArt would be a good tag. I just feel #HumanMade is a bit too... wide and undefined. Every building is Human-made. And #HumanArt kind of feels.. off for me. I can't define it, it just doesn't sound right!

#HandmadeArt *possibly* cuts into painter territory? But it's not like digital artists don't use their hands to make their art, so I think it's fine ^^