DOG by Matthew Van Fleet is, hands down, my favorite tab/flap/texture book for babies. Each of my three children has gotten a new copy, not because it isn't sturdy (it is), but because it has gotten WAY more than its fair share of loving!
The fuzzy tails and ears and sticky tongue are legitimately fun to touch, the pull-tabs are easy to manipulate for small hands, and the moving tails and legs are sturdy. There are between 7-15 words per page spread- a good mix of early vocab (dog, big, little, shake, ears, etc) with more advanced words (quake, floppy, howl, etc) to keep babies interested. The pictures are clear and varied, the rhyme flows well and has humor! It is everything a great baby book should be! My three kids have all adored this book.
Matthew Van Fleet has a few other, similar books- CAT and MOO. Which also seem excellent. Our family has had dogs, so our babies have been more enamored of DOG than the others!