There are so many and it's really tough to nail a lock-down definition on "one hit wonder." Here are a few huge ones, for me, that are pretty popular bands in the UK but not so much on my side of the pond:
The Verve
Madness
The Proclaimers
Chumbawamba
Blur
Cornershop
Also - Biz Markie. Kind of bums me out that his career flamed out so hard. And if anyone considers Violent Femmes to be a one hit wonder, then fuck me I might as well just sharpen my earbuds and fall on them already because I do not want to live in a world where people think of the Violent Femmes as a one hit wonder