Don't give me that look, Izzy. Everything here is SFW.
1. Satisfying the "you must be tall enough to ride" requirement at the amusement parks.
2. Skewering marshmallows for roasting on an open fire.
3. Breaking the driver's seat window to escape from a sinking car.
4. Hooves-free piñata fun.
5. Drape some waterproof fabric over your horn to create a hooves-free umbrella.
6. Easily hold a clean roll of toilet paper when you're in a porta-potty and the floor and walls aren't very hygienic.
7. Easily hold a half-dozen bagels when the bagel shop runs out of boxes.
8. Easily hold a half-dozen glazed donuts when Dunkin' Donuts runs out of boxes.
9. Defending yourself from the angry mob that insists that Krispy Kreme is better.
10. Easily hold a dozen glazed donuts when Krispy Kreme runs out of boxes. Krispy Kreme is superior and never runs out of boxes
11. Ringing the school bell, Pinkie Pie style.
12. Playing seven handbells at once by hanging them around your head like a baby mobile.
13. Playing volleyball, except with horns and a non-inflatable ball.
My headcanon is that volleyball was a popular sport among G5 unicorns before magic returned. Hence why Izzy was so skilled at bouncing the baked beans can.
14. Tossing pizza dough.
15. Opening up your Hearth's Warming presents as quickly as possible. Just be careful not to puncture a hole through your brand new iPhone 13 Pro Max.
16. Looking like a cool headbanger when you play tee ball.
17. Wearing your engagement ring after Sunny Starscout proposes marriage to you

And last, but not least...
18. Opening a tin of baked beans.

* From my blog post: https://www.fimfiction.net/blog/968288/18-non-magical-ways-to-use-a-unicorn-horn-that-isnt-you-know-what

7590100
<golf clap>

7590100

"you know what"

I don't think I do.

Please, enlighten me.