Note: RE2, Latest Beta being played.

Suggest you look in the PDA - details on the ores and what type of systems you can find them in are shown there.

Alternatively - you can look at the Empyrion Buddy (which is also linked from the PDA) :
https://empyrionbuddy.com/pda/palladium-eden_pda_8J4aO4e

Cannot tell you exactly where to find them as your galaxy will be generated randomly and will be different to my randomly generated galaxy!

Thanks for the reply - must admit that I glanced at the PDA and then promptly forgot about it.. like most Instruction Manuals, tbh. I'm a little annoyed to find that Palladium is only found in Hostile Territories as I'm currently deep in Tranquillity Territory.