Luna/Terra/Sol/Astra was a bit pretentious but at least the sizing makes sense. (I imagined the meeting... "Ok guys, we're getting mogged on naming... what's more epic than a Myth?" -"The SUN!")
Anthropic makes sense with the literary "scale" naming, mostly.
Is a Carbon bigger than an Argon though? Maybe it has to do with the atomic number?
It's possible Argon/Carbon are pro sized, but given the internal rumblings and that it is based on a fresh pretrain, it makes most sense for it to be a "big" model.
Google did at one point have an "Ultra" sized model, but nothing more came of it after 1.5 Ultra.