4th Gen Another one of those team threads, help please!

ok so here it is, can someone give me a hand and complete my team? I'm missing one pokemon and I'm trying to decide between different possibilities, I'd like to know your opinions!

The rest of the team is: (not putting movesets, just the type)

Mew (sp atker)
Snorlax (returner)
Swampert (curse/earthquaker)
Blissey (hardboiled priest)
Arcanine (high atk high speed, you don't wanna meet him XD)
???

I don't want any team ratings or moveset sugestions all I want is your opinions on who would be good for taking my mising spot!

Thanks in advance!

Try this:
https://pokemon.marriland.com/diamond_pearl/team_builder/

It lets you see what your team overall is vulnerable to and particularly strong against. Then from there you can decide what's lacking and which Pokemon will help to fill the hole.

ok man thanks! I'll definitely try it out!