Currently it's the KVB-556M. Powder Valley has the Tula Primers, as does Graf & Sons.
If you look at the MSDS sheets, CCI and Remington and Winchester and TulAmmo all use normal lead styphnate (aka, lead trinitroresorcinate or lead styphnate), while Federal uses basic lead styphnate (aka, lead hydroxide 2,4,6 trinitroresorcinate, or lead styphnate hydroxide). That latter compound is a bit more sensitive, apparently, but it's also used in military primers with sensitivity tempered by cup and/or anvil geometry. Apparently Federal thinks it ignites more consistently. The TulAmmo primers have a compound I don't see in anyone else's primers called monosubstituted potassium styphate. It's in both their standard and non-toxic primers. Perhaps it's their secret to uniformity. I don't know enough about explosive chemistry to guess. Remington has lead trinitroresorcinate in additions to lead styphnate. Winchester has lead thiocyanate in addition to lead styphnate. So more than one lead compound is involved in those two brands of lead-bearing primers.
There's no PETN in any of the primer MSDS's for non-toxic primers that I've found. The compound that substitutes for lead styphnate in the NT primers is DDNP (diazodinitrophenol). It's brissance is higher than lead styphnate's, apparently, because larger flash holes are normally used in large primer versions so they can vent gas pressure fast enough to keep it from backing the cup out of the primer pocket hard and fast enough to pierce. The flash hole in small primer pockets seems to be large enough in proportion to the rest of the pocket that it doesn't need to be modified for this. That's why it's become standard in NT .45 Auto brass to use a small primer pocket, where you used to see a large primer NT .45 Auto cases, but with a 1/8" flash hole. There's a good article on the problem, here