You want to make sure they are as non-porous as possible, and be sure to use the right kind of lube with them. Condoms are generally recommended for even slightly porous materials, but they're usually a pretty good idea in any case.

I recommend silicone and the like. Make sure the toys are phthalate-free, non-toxic materials if they are, for example, TPE. Don't get PVC toys, they're cheap and not worth it in any case. You can get solid glass ones, but that depends on if that's the texture you're looking for, and I would definitely only be okay with that from a brand I trust.

Vixen Creations and Bad Dragon are both two very reputable toy sellers that make very high-quality toys.

I hope you'll find success in your search!

Although, I do perceive much of these dildos cater to females. Cool!!!!!!!!!!