These work wonderfully with sugar cookie dough, but I haven't tried any other kinds of medium to play with. The sizes vary, but the average cutter size will be around 3 inches.
All the letters in the alphabet and single digit numbers, and a question mark
Lots of hearts: three scalloped and three smooth in different sizes, a heart with an arrow, and a double heart
Easter: bunny face, bunny, egg, cross,
Halloween: big pumpkin, small pumpkin, ghost, scared cat, bat, witch, haunted house
Christmas: small christmas tree, large christmas tree, candy cane, snowman, stocking
4th of July: flag
Sports: trophy, baseball cap, football helmet, football
People: gingerbread-shaped small boy and girl, and gingerbread-shaped large boy and girl, hand, foot
Dinosaurs: stegosaurus, T-rex
Machines: train, car, plane, fire engine, truck
Animals: dog, fish, 2 sizes of teddy bear, duck
Misc: 3 different sized smooth circles, 3 different sized scalloped circles, bell, shooting star, cowboy hat, boot, butterfly, flower, sun, tulip
All in all, a pretty complete set, I have nothing to complain about in terms of variety, ease of use, quality of the item, or anything else. Highly recommended!