The top 3 Stay-A-Float Tire Sealant for Onewheel GT S-Series, GT, XR, Pint X, & Pint™ | The Float Life | Onewheel Tire Sealant alternatives are
GOAT 5″ (5″ hubs only) - FlightFins,
Pioneer Tire, and
ThunderCat Tire.
If these 3 options don't work for you, we've listed more alternatives below.