No sooner do I give up on looking for them do I hit the jackpot. Like, every other jump on the return trip has an NSP, and one of them has a crystal shard site too! Once I get back to the FC I'll dump the bookmarks here.
Alright, the following systems have the Pods in them. Cereulum being the most common and Viride being most rare.
Whookua JXA d1-5
Whookua SK-A c3-0
Pre Eaeb GE-E d13-1
Pre Eaeb CY-F d12-10 -- Crystalline Structure Bio Site with Tellurium on B 10 A
Pre Eaeb EW-L c24-3
Pre Eaeb KZ-M d8-9
Pre Eaeb HG-F c14-2
Pre Eaeb BA-H c13-3
Pre Eaeb WG-S d5-5
After the last one, I did not find any more back to the carrier.
Cutoff occurred at around (3400, -77, 10990); not sure how this factors in.
Codex observations held correct until that cutoff occurred, within the cutoff limits even a single water world in the system was enough to have a proto lagrange cloud with pods in them.
They can occur within rings of planets, but mostly found in proto lagrange accompanied by icy and metallic crystals. In the rings they may show up by themselves.
Research limpet will return the various Pod tissue samples as loot.