I would generally agree with the recommendation of Durable for toys that are likely to be dropped, thrown, or otherwise stressed. I would also like to emphasize the importance of post-curing the parts properly, not just for the mechanical properties, but to help get rid of uncured resin. None of our resins are biocompatible except the biocompatible ones, and even those are only biocompatible after a strict post-curing schedule. So, for handling by humans, it’s good to make sure your parts aren’t tacky, and it’s never a bad idea to wash hands between handling Formlabs parts and eating.
Durable for sure. It is literally impossible to break, although it will deform.
Not to be too contrarian, but I can assure you that it is quite possible to break Durable. (and we measure it in the lab). Formlabs has yet to release an Indestructible or Nigh-Invulnerable resin. Tough resin could be good for higher-detail parts, but it is a bit less impact resistant. Grey Pro, Rigid, Elastic, and Flexible could also have roles in some kinds of toys or toy prototypes, but Durable is generally going to stand up to the harshest handling/play conditions, in my opinion.