Ska is a pretty diverse genre, if you list some genres/bands she likes you may get some better examples. Also it’s like 3am so I’m posting so I can do this later.

Big edit time:

Ok so, if you want current stuff I would check out Bad Time Records: https://badtimerecords.bandcamp.com/artists

They’ve got a pretty good selection of stuff, and most of those bands are still playing shows regularly if that’s a thing you’re into.

Assuming you want fairly normal stuff I’d suggest JER, Catbite, and Kill Lincoln, but check out all the artists on that page for various different styles.

If you want older stuff, you’ve got original stuff (60’s) like the Skatalites, Boots & the Maytals, the Ethiopians, etc. a lot more reggae like.

You can get into two-tone (a lot of what’s been suggested already, 80’s stuff) with Selector, Madness, the Specials, Bad Manners, etc. a bit more chill than newer stuff, but definitely in what’s more defined as ska and less reggae than traditional stuff.

Or the Third Wave was a lot more poppy late 90’s stuff. Big popular bands like Reel Big Fish, Less Than Jake, Goldfinger, No Doubt, etc. Plenty of other good bands like Blue Meanies, Fishbone, Operation Ivy, Catch 22, etc.

Plenty of Skacore bands, mix in a bit of heavier stuff like Folly, Flaming Tsunamis, Best of the Worst.

Punk ska bands like Against All Authority, the Fad, Omnigone, Stuck Lucky, etc.

Plenty of punk bands that flirt with Ska like the Flatliners, NoFX, etc.

Japanese Ska like Tokyo Ska Paradise Orchestra, Oreskaband, Potshot, Free Kick, S.M.N., etc.