I was gifted 13 Snow Pumpkins by Jaime for turning in a fetch quest. I'm guessing they're not fully implemented yet because when I turned them into seeds I can't plant them. It says "Winter only" and it is Winter 16 in the game. The seeds are called "Pumpkin Snow" rather than "Snow Pumpkin" like the crop. Clicking on them only gives the option for "info" not "hold".
I've been gifted a few other things I saw weren't implemented yet like titanium ore and bars and titanium tools.