Must Haves for Mixed Drinks?

Hi all! I (21) am kicking off my last year of college and hosting some dinner parties with friends. We’re doing a couple of dinners between now and Christmas, just casual.

I used to be a barista, so I’ve got an espresso machine w/ a steam wand, about 300 types of tea, a dozen syrups, etc. So I thought I’d try my hand at cocktails and the like since I enjoy the process with nonalcoholic drinks. None of my friends are particularly heavy drinkers, so I’m looking for some staples to get for some casual fun drinks through the holidays.

If anyone has any recommendations on mixers, liquor, shelf stable additions, and recipes, they’d be greatly appreciated 🙂

Preferably keeping it on the cheaper side since im a college student, but I would like to have some things on hand to make fun drinks whenever people come around!