Rousseau Gambit (great for lower rated players)
Sicilan Defense
Scotch Opening
Fun Openings
Scotch is fun and solid, if you feel frisky you can't switch to the scotch gambit which leads to fireworks 🎇🎇
"Fun" is a relative word. What one finds fun another finds boring or stressful.
Many would say the Najdorf or the Max Lange Attack. I don't find either of those to be fun. I find them both stressful. Fun, to me, are the Petroff and e6-Dutch lines.
Although I refuse to "take sides" on whether or not it is objectively good, against 1. e4 I can vouch for the Sandinavian being "fun". I played it with 2..., Nf6 in the mid-80s when the Iceladndic Gambit was new and had a ball. I played it with 2..., Qxd5 in the mid-90s and equalised easily with free central play. Admittedly the world has moved on since way back then. The dinosaurs have had an extinction event, Buster Keaton no longer tops the bill at that new-fangled cinematograph thing the young folks speak so highly of, and so on. If you can bear to learn the 2..., Nf6 theory, that still seems to be the "road less travelled" in which an opponent might be less well-prepared.
I know e4 and e5, nd I'm currently learning the caro-kann, but that's a bit basic and boring. Is there any fun, unique openings that are actually good openings?