Here's my notes on architecture codenames:
https://doku.stenoweb.net/doku.php?id=macdex:architectures
Adapted from:
https://macinfo.de/hardware/hardware.html
Wikipedia has a list of codenames, but these are really product-oriented, rather than architecture-oriented:
https://en.wikipedia.org/wiki/List_of_Apple_codenames
A codename for the 630/6200/6300/1400/2300/PB5300 architecture isn't identified anywhere I've seen. I usually just refer to it as "the 630+ architecture".
It depends on the context but I usually recommend either talking about specific models, groups of models by their numbers, or by describing what you mean, e.g. "the 630-based PPC Macs" or "601/604 PCI PowerMacs" or "603 PCI Macs" or "603 PCI Mac Desktops" or "the 6360, 6400, and 5400" depending on what you're really targeting.
For example, if you say "Alchemy" but you mean something that could also apply to Gazelle, why not just say "603 PCI desktops"?
Looking through the list, using a lot of these nicknames really just amounts to showing off, since a lot of them refer to very specific models, e.g. Nitro really only refers to the 8500/8600 and TNT really only refers to the 7500/7600/7300.
(Depending on where you look: "PowerSurge can refer to a larger group of models, but it's an incredibly uncommonly used nickname/codename/grouping.)