Sizes have been added to Pledge levels, but, here are some here as well for easier access! :)

BIteBound backpacks:
Size: Interior pouch 10" x 8" So plenty of room!!!
Height is over 16" without tail!!
Cobweb & Crumb:  20" with tail
Whisper & Wickett: 21" with tail
Toffee & Thimble:  24" with tail

Bats: 13-14" tall including the ears

Stitched cats:
15-16" tall  excluding the tail
around 20" tall with the tail

Plague Dr.: Around 17-18" long

BlackTop Circus:
Poppet: Poppet is weighted (43oz that's over 2lbs!!!) and 25" from tail tip to nose tip!
Grimoire: Similar to Poppet in size and weight, but shorter due to short tail
(other unlocked designs will be similar as well to Poppet)

Jackalopes: Around 14-14.5" tall, antlers are floppy (Only on Hemlock) and ears are bendable


Hope this helps! :)