Someone finally did it, although I’d like someone to do the ST version instead.

PixiEditor is an open-source Universal 2D Graphics Editor.

Resprite: Pixel Art and animated sprite editor for iOS, Android and Desktop.

Blockbench puts all the tools at your disposal to make the creation process of low-poly models as easy as possible.

Use cuboids to get that Minecraft aesthetic, or create complex low-poly shapes using the mesh modeling tools!