If you've ever been to an event in Tulsa, chances are something there came from Earl's party supply.
I don't think there's anything they don't have... for weddings, you can get tables, chairs, linens, place settings, etc.
For casual parties, you can get decorations, party favors, gag gifts, etc.
And they have some unusual stuff to rent too... if you're planning a "casino night", you can rent casino games like Roulette & blackjack tables... just remember that it's illegal to play for real money in the state of OK. Try a "Candy Casino" instead... each type of candy is a different denomination.