4th Gen A Pokemon that could've fit into the Gen 4 dex

Do you think there's a Pokemon from a previous/future generation that would've fit into the Sinnoh dex (As in be a new Pokemon in Gen 4)?

I think Milotic could've made sense. Arcanine as well.

Chimecho and Luvdisc? Yup, that'd be it.

That other heart Pokémon that hugs things. Luvdisc and Alomoma are near identical and would have been prime candidates to be evolutions.

I do think Luvdisk and Alomola should have been. They really should have been evolutions of each other. I also think Feebas and Milotic could fit in there as well.

Urm Milotic is in this gen's dex? For both DP and Plat even.

I thought this gen has already a decent dex so there wasn't anything more I could ask honestly. Maybe more Ice mons I guess?

Edit: Oh wait. The OP meant an existing mon that could make sense as a new mon for this gen. But again I kinda feel all the new mons here felt complete so I can't really ask for more tbh.