I can give you a basic rundown of when, and who each pet was released with. My stickied list that was mentioned has (small) photos of them next to their proper characters, but you can find probably find larger images on sites like Amazon and Flickr.
Some pets were released more than once under different dolls.
2010:
-Signature Frankie, with pet dog hybrid, Watzit (re-released in 2013 in Europe)
-Signature Draculaura, with pet bat, Count Fabulous (re-released in 2012, and 2013 in Europe)
-Signature Clawdeen, with pet cat, Crescent (re-released in 2013 in Europe)
-Signature Lagoona, with pet piranha Neptuna (pink version)
-Signature Cleo and Deuce 2-pack, with pet cobra Hissette, and pet rat, Perseus
-Signature Ghoulia, with pet owl, Sir Hoots-A-Lot
-Signature Holt, with pet chameleon, Crossfade (red and orange version)
-San Diego Comic Con exclusive black and white Frankie, with pet dog hybrid, Watzit (2nd release of this pet)
2011
-Signature Clawd and Draculaura 2-pack, with pet gargoyle bulldog, Rockseena
-Signature Spectra, with pet ghost ferret, Rhuen (re-released in 2012)
-Signature Abbey, with pet woolly mammoth, Shiver (re-released in 2012)
-Signature Toralei, with pet sabertooth tiger, Sweet Fang
-Dead Tired Hydration Station Lagoona playset, with pet piranha, Neptuna (2nd release of this pet, pink version, no difference to signature release)
2012:
-Signature Operetta, with pet spider, Memphis "Daddy-O" Longlegs
-Signature Nefera, with pet scarab beetle, Azura
-Signature Jackson, with pet chameleon, Crossfade (2nd release of this pet, green and yellow version)
-Signature Rochelle, with pet gargoyle griffin, Roux
-Signature Robecca, with pet mechanical penguin, Captain Penny
-Signature Venus, with pet venus flytrap, Chewlian
-Target exclusive Howleen and Clawdeen 2-pack, with pet Hedgehog, Cushion (grey and orange spiked version)
-Toys R' Us Ghoulia Scooter playset, with pet owl, Sir Hoots-A-Lot (2nd release of this pet, same as signature version, though he comes with removable goggles)
-Toys R' Us Draculaura Powder Room playset, with pet bat, Count Fabulous (2nd release of this pet, wearing bathrobe)
2013:
(unreleased, planned for the summer)
-13 Wishes Lagoona, with pet piranha, Neptuna (3rd release of this pet, purple version)
-13 Wishes Howleen, with pet hedgehog, Cushion (2nd release of this pet, pink spiked version)
-13 Wishes Twyla, with pet stuffed bunny (name currently unknown)
-13 Wishes Gigi, with pet scorpion (name currently unknown)