What can White Walkers raise from the dead?

Question

Seeing as how in Game of Thrones S06E05 ("Door")

Summer (Bran's Direwolf) dies defending Bran from the White Walkers

Is there any limitations on what White Walkers can resurrect? Is there any chance of a comeback for that character?

Answer 1

Episode S02E10 showed us that the White Walkers can mount undead horses. But in the context of the show, it seems to be the only non-human species to be raised from the dead.

In the books, we furthermore get some tales

"Some stories speak of them riding the corpses of dead animals. Bears, direwolves, mammoths, horses, it makes no matter, so long as the beast is dead. The one that killed Small Paul was riding a dead horse, so that part’s plainly true. Some accounts speak of giant ice spiders too."

_{A Dance with Dragons - chapter 7 (Jon II)}

an undead bear

A snow bear crashed through the brush, huge and skeletal, half its head sloughed away to reveal the skull beneath. Summer and his pack fell upon it and tore it into pieces. Afterward they gorged, though the meat was rotted and half-frozen, and moved even as they ate it.

_{A Dance with Dragons - chapter 34 (Bran II)}

and a message from Hardhome

"Dead things in the woods. [...]. Dead things in the water."

_{A Dance with Dragons - chapter 58 (Jon XII)}