If you haven't picked a costume yet — or just want to know what you'll be seeing a lot of at parties and parades this year — here are top 10 lists from two reliable sources: Google, which tracks the most-searched costumes, and the National Retail Federation, which polls consumers in early September.

First, Google lists the top 500 costume searches — you can even look specifically at your city to see what's trending near you.

Nationally, here are the top 10 most-searched costumes of 2015:

1. Harley Quinn

What you need: Pigtails or a jester hat, and dual colors — usually red and black, although this lovely lady chose red and blue.

2. Star Wars

What you need: Just buy it already. Or, if you have a brown or black bathrobe you can pull off an Anakin Skywalker pretty easily. Still, every Jedi needs a light saber.

3. Superhero

What you need: Chiseled abs — or the foam to fake it. So many options here! Superman. Iron-Man. The Incredibles. Take your pick and find some Lycra.

4. Pirate

What you need: Embrace your inner Jack Sparrow for a swarthy-spooky-swashbuckling time.

5. Batman

What you need: The mask (duh). And a cape (he's the Caped Crusader!). Optional: Utility belt. Optional: The abs (see “Superhero” above).

6. Minnie Mouse

What you need: Yellow heels, a polka-dot dress and a bow for your hair — er, ears.

7. Witch

What you need: Anything goes. The witch costume is a classic, in part, for its versatility. Go seamlessly from cleaning to trick-or-treating (carry that broom right out the door!). Go old-school with green face paint or a wart. Go low-maintenance by not plucking that chin hair. Pointy hat and striped socks are a plus.

8. Minions

What you need: Denim overalls. Goggles. Yellow facepaint. Boom. (But you still won't meet Sandra Bullock, sorry.)

9. Joker

What you need: Green hair dye, white face paint and red lipstick for that creepy smile.

10. Wonder Woman

What you need: Gold sweat bands, a red tank top and a royal blue skirt. Or, in some cases, boy shorts. Buy some white star stickers (or, if you're willing to throw out said skirt or boy shorts, just use White-Out) and you're in business.

10 most popular Halloween costumes for 2015