Figurines are hot business right now. Having Triss, Yennefer, Ciri, Keira, Geralt, Vesemir, Lambert, Zoltan, etc..
Hell, throw in Monsters as well. Not entirely sure about production or reasonable pricing for these, some figurines can go anywhere from $30 - $300.
GWENT needs to be a thing, with It's own "Battlefield" playmat. The rules carry over, and you collect cards for each of the Decks, or simply have decks completed and sell each deck separately.
May not be comparable to, say.. MAGIC, but It's such a well done card game and needs to be a real thing, in homes.
Put Poker Dice boxes in production as well, with Witcher themed Dice. It's simple, yes, and anyone can play with just a handful of everyday Dice, but It's the box in which you play on will be the selling point. Especially if It's well made.