There are a few existing diceless systems that could be adopted, hacked, or scavenged, but there's also a golden opportunity to come up with something novel. I'm sure there will be plenty of attempts to find a way to hack existing systems that use dice, although of course that's tricky if you were wanting to do a PbtA design or something like that where the numbers matter. (I know Fate has a "Deck of Fate" that you can use in place of dice, which technically adheres to the letter of the jam, although it's arguable whether it's in the spirit).
As for artistic assets, always credit creators, respect intellectual property rights, and get permission.
