Nothing hard like antlers or yak chews just yet as your pup is teething and you don't want their baby teeth to be loosened and come out early.
Nylabone and Benebone do some puppy appropriate chew toys, if you amazon search those two you should find a decent amount of options. Kongs are always good as well just don't make it difficult at the start as the pup might decide its too hard and give up
I would advise but I managed to miss Colin’s teething entirely! I suspect most of his teeth came out when he was hanging from Millie lurcher’s collar as they played growly games in all honesty....
He just has normal toys - a couple of Kongs and a few stuffed squeaky toys that he has mostly eviscerated now - I have a personal dislike for nylabones and the like, they have always seemed to hard for the dogs for my liking, but usefully I’ve never had dogs which were particularly keen on them either ?
Have a look at chew wood. It doesn’t look too hard, not as hard as Nylabones, although I like the puppy version. Chew wood is enough to get teeth into without breaking them off, satisfyingly soft enough but with resistance. Have you tried frozen carrots or a twisted soaked frozen tea towel?
Small dog who must have something in his gob At All Times Or Else found Nylabone Power too hard, Flexi and Strong too soft, but Petface Duo-Chews (available in three sizes and three flavours) were just right.