I found this by googling polymer clay sealer. I was going to suggest Clear Acrylic Sealer but it doesn't look like it's on the list. I hope this helps!
For a finish on polymer clay, there are several choices
... you can leave clay items without a finish (they don't *need* to be finished as long as they're just clay), or give them a sheen, or give them a high glassy shine.
........there are 2 basic ways of getting a sheen or glassy shine ...one is applying a liquid or wax, and the other is wet-sanding then buffing.
1. the LIQUID finishes we generally use for clay are:
---Rustoleum's Diamond Interior Varathane (used to be called Flecto) (at hardware store with wood finishes), or any other acrylic interior polyurethane
---Future floor polish, or any other acrylic floor polish like Mop 'N Glo, Johnson's Klir, etc.
---finishes put out specifically for polymer clay (like Fimo's or Sculpey's)
---acrylic-based clear nail polish... but not enamel-based!)
---clear liquid clays (Fimo's or KatoPolyclay's... or apply TLS in thin layers)
---Liquid Glass (by Aristocrat) --2 pt.
---diluted white glue
---dimensional glues/adhesives (PolyGlaze, etc.)...easily scratched if not sealed
---UTEE (Ultra Thick Embossing Powder)... easily scratched if not covered sealed