Hello r/cocktails. I have been designated unofficial bartender for an upcoming party. There are going to be probably between 30 - 50 people. They were going through their liquor cabinet, and they have a bunch of gin, vodka, and tequila. The party is harvest themed. I was hoping someone might have an idea for a punch base I could mix up in a separate container that would work with either of the three spirits, so people could take some punch and add the liquor of their choosing. Ideally, in keeping with the harvest theme, I was thinking of trying to do something with some fall type spices (cinnamon, nutmeg, etc.) but I'm not sure if there's a one size fits all option that will work with those three liquors.

Thanks in advance!