I think atm the most rarest of my Winx merch are two complete little sticker albums by Merlin: the alphabethic one (which is a combination of the season 1-3) and an Enchantix one. I'm really into Winx sticker albums so they're my treasures
The most rare doll I own is maybe a ballerina Layla by Mattel but she's not complete, I'm missing her legwarmers. Also biker Stella by Mattel seems to be rare in many countries (but she's kinda common in Finland and I still have the one I got when I was a kid).
And I also have an Alfea castle which was sold only in Raindow Magicland (or at least I suppose so?) It used to have some makeup stuff inside of it but mine is empty. So this is not the same than the one for magical minis or the super big one for dolls but a different third one. I'll take some photos of it later
