Okay! There's DuraClear Matte Varnish at my Walmart, do you think that brand works?
It says polyurethane.

i missed seeing the Northern Lights last night. i didn't think it would make it so far south. i looked out around 10pm or so and didn't see anything. but apparently you can use your phone camera to see it. i didn't know i'll try again tonight.

also the neighbor diagonal to us keeps trying to run birds off from his backyard by putting up all this reflective junk. i guess their precious pool is more important than allowing birds to be around. now he seems to be lining the fence with tin foil if you don't like birds don't move to the burbs. they were here first! the trees i'm planting along the fence can't grow fast enough.

Is your pony a G1?

I second BC's advice, polyurethane varnish should do the trick.

Mod Podge was once the recommended sealer, but it's really not good for most objects. It's great with paper. I live in a very hot and humid climate and have spent years looking for a sealer that won't go tacky. These days, I choose to leave my customs mostly unsealed, but when I do use one, I have the Vallejo.