My son likes to sleep super warm but won't tolerate blankets or sleep sacks. Often it works to size up in cotton pj's (the Gap ones fit, as do Walmarts organic), and size up in Carter's fleece sleepers.
If that doesn't work we do a cotton T and a long sleeved shirt, cotton pants and fleece sweatpants, and tuck a shirt into the outer pants.
Then I add a pair of my wool socks, pulled up over his thighs. Looks ridiculous but it works! 3 layers over the legs and torso, 2 on feet.