Another example piece for the flag YCH, for ObeyTheSnarf !
If you'd like a pic like this yourself, the YCH details can be found here: https://www.weasyl.com/~armeddillo/submissions/1792299/flag-ych

If I'm being honest, Mettaton does seem like the kind to strongly support trans people; it doesn't feel too off at all to have him holding the pride flag.

I don't typically draw canon characters from established media, especially for commissions, but this is an exception because it's an example.