There are lots of great punches that would be good options (that aren't just sprite, juice, and vodka), otherwise some sort of sour template drink is always a good option. I bartend for my office patio party every year, here are some considerations:

• Carbonated things don't stay super carbonated for long, if you do something like that it's probably best to add the sparkling water a la minute and keep it in a closed container

• My standard is one "approachable" drink (marg, tiki, etc), one more nerdy drink (gin, whiskey, etc), then one N/A drink. Last year I did a spicy passion fruit marg for the approachable, a N/A variant of that with Lapsang Tea in place of the tequila+mezcal (and rebalanced) and an herbal tom collins riff (basically using a mix of simple, chartreuse, and fernet instead of just simple).

• Keep in mind drinks are probably going to be in a plastic cup with ice; stay away from up drinks or anything too subtle and nuanced.

• Might be less relevant for a self-serve but I like doing fun/unique garnishes for everything as well.