In fact for Ancient Artefact taken from here: EDDB Commodities you have both "Ancient Artefact (USS)" and "Guardian Relic". Are you sure it is the same thing or is it just a mistake from eddb?Galactic Travel Guides are the item used for the "CGs" getting factions to colonia. if they are still buyable at Bluford, you can only get 10t (without tricks).
Ancient Artefact are a guardian commodity, you get them at any guardian site or ruin (those thingies coming out of the groud, and can be shot down).
Large Survey data caches used to spawn in degraded USS in deep space.
as for Gene Banks, Fossile Remnants and Space Pioneer Relicts - i haven't found any till now at private courier/military courier vessels, maybe there is a knack of how to find them.
And thx for LSDC, i'll take a look at these.