Judging from the pets coming in 7.1, it looks like this is finally coming up. First, the obvious ones:
Ironbound Proto-Whelp: Razorscale
Snobold Runt: Beasts of Northrend
Winter Rageling: Hodir
Nerubian Swarmer: Anub'arak
Runeforged Servitor: Iron Council
Igneous Flameling: Ignis
Creeping Tentacle: Gonna go out on a limb here and guess Yogg.
Boneshard: Almost certainly a Lil' Marrowgar
Some others have less obvious bosses.
G0-R41-0N Ultratonk: Probably Mimiron, could be Flame Leviathan or XT though.
Blightbreath: Probably a mini Festergut, could be from Putricide or any boss in the plague wing.
Blood Boil: Possibly Deathbringer Saurfang, could be from Blood Queen too.
Soulbroken Whelpling: Probably Sindragosa, but could be Valithria.
Some may or may not even be in there:
Sanctum Cub: Auriaya?
Squire/Gruntling: Faction Champs?
Drudge Ghoul and Wicked Soul both feel like Arthas drops, but if precedent holds, there can be only one. Wicked Soul might be the meta reward.
What's everyone else think?