I am absolutely of merino / cotton blends for light wearables as they do not keep warmth too much (and I am not too fond of being warm).
For winter wearables, alpaca is a must-have as it is quite affordable (compared to more expensive wool) very soft and very warm.
Hi :) I think Merino-cotton or alpaca blends are a safe bet... If you can afford more expensive yarns, I'd suggest mohair, which is very fine but as soft as a kitten. On the less expensive side, I think a velvet/chenille could be very warm and not itchy, even if it's still acrylic. Happy crafting :)