I'm posting a connector map set for Winter and Grasslands. I've checked what sets are compatibile with this connector in terms of layout and texture, here is the list:
Winter:
Winter Outpost A, B, C, D
Frozen City A, B
Winter A, B
Winter River
Ice Crystal Field
Winter Settlements A, B, C, D
Grasslands:
Alpine Lakes A, B, C, D
Alpine Ridge A, B, C, D
Riverside A, B, C, D
Dragon Moutains A, B, C, D
That being said, Dragon Moutains would look rather odd when adding it by connector to winter biomes, as one is winter and the other one is tropical! It's a shame there aren't more maps that could work in that way, but I will keep the connector in mind next time I work on something either grassland or winter themed, to add something more to the combo list.
Have fun with this map set, and best wishes to everyone for the new year!