Here are some of mine:
The red spike on Gardevoir and Gallade's chest is usually solid and hard when touched, making it hard for them to be embraced directly.
However, if a human which the Gardevoir/Gallade has developed strong connection with attempts to hug them, the spike phases right through the person in question, allowing for the Gardevoir/Gallade's heart to be physically connected to the person's.
A similar thing happens if the person in question is by any way endangered by the spike (for example tripping and falling into Gardevoir/Gallade's chest or anything of this sort).
The dress is not made out of flesh, but out of fabric that the Gardevoir make themselves by using materials they find in the wild. The dress can be taken off anytime. Their bodies are completely white, with the exception of their hair.
Their hair can grow and can be stylized in any way they desire, but most prefer to have it as a bobcut for some reason.
They don't originally belong in the Amorphous Egg group.
The Wild Ralts-Line Pokémon live in seculded villages and tribes, sometimes far away from humans, sometimes close. Their culture and traditions are not very different from those of the humans.