>>25145082Lucario doesn't look any less Steel than Mawile.
With the whole "deceiver" gimmick, you'd think Mawile would be a Dark-type, but no, it's Steel because the "mouth" on its head is supposedly a set of steel horns.
They've got metallic horns/spikes growing out of their bodies, so it can be assumed that the bones inside of their bodies are made of metal too.
I went with Jirachi because it has absolutely nothing that visually identifies it as a Steel-type.