I don't believe that filtering op_return is possible. It has been around 10 years... and any op_return of any size is enough space for degens to 'create' meme coins. A "rune" is just an op_return with a name... "indicating" arbitrarily that an output or outputs are 'memecoins'. It's really silly. Couldn't other data schemes effectively do the same thing? The vast majority of inscriptions aren't even jpegs... they're 'tokens' or indicators for tokens which op_return can already do.