I mean anything that currently is allowed but would be restricted post activation. Post activation people can use the old and less utxo efficient method of P2sh wrapping to embed data. “Honest” spammers who just want their pictures on chain could choose this method and if they continued doing their spam at similar volume the chain would suffer utxo bloat in excess of the current norm. The issue I see is that in the absence of spam the lack of demand for block space makes a dedicated utxo attack feasible. Even if the attacker bloated the utxo over 2 years it would severely damage node runners. People are complaining about a couple hundred in drive upgrades because of v30…you think they are going to spend thousands for a 32gig machine?