Lara Croft... (The classic look)
or
If you have access to a massive oversized sword...
Cloud Strife...?
Well, I was going to suggest Pyramid head, but that might be even worse than the Master Chief outfit.
Everyone wants to dress up like Ivy:
Ha! The oldies but goodies. Of course, Mylo:
Pretty simple: pink suspender overalls, blue tshirt, red miner's hat, pickaxe, old light fixture for newly mined huge crystal, and red clown shoe boots.
And for the special lady of the party, of course Jill:
Also simple: Black ankle boots, green sleeveless bodysuit, long blonde wig, weapons (knife, spinning blade, jump arrows), lucky charms (apples, flaming bird, fish, frog), and enemies (ants, crabs, alligators, beehives, stalactites--maybe even a scary knight). Icons, of course, except the apples Also a little stash of gems and keys.