Color/texture scheme variants

Color/texture scheme variants of object/wall/door and window assets and variant matches for stairs.
It's frustrating making a map that has a dark wood or stone texture scheme but a lot of the available assets aren't skinned to match. And stairs, stairs that go up that are 2x2, but the closest equivalent going down is 1x2.
Assets that match texture schemes or the ability to pick the texture would be so awesome.