Just thinking about the Lore, it's ripe for pickings!
There is the mystery of the Colonisation Generation Ship Artemis. It set off with 5000 souls in Cryo Stasis at Quantum Drive speeds intending to put a colony on a planet 200 years travel away but vanished on route. Look it up, artefacts have been found, a hull plate, a thruster, a body suspected to be the mechanic but lost in efforts to recover it... The ship is still missing... will you be the one to find it?
I believe there is also a planet somewhere in the Kabal system which is a time-capsule of Tevarin stuff which appears to have just been... abandoned. It's where they got the plans to be able to build the Prowler Dropship replica from.
Then there is Kaleeth itself which was the Tevar Home World, crewely terraformed by the UEE into what we know today as Planet Jalan, the fourth planet of the Elysium system.
And there is Garron 2, another terraformed planet... It was choc full of life including an Emerging Sentient Species which was wiped out of existence by Terraforming which also wiped out the Messer Era by being the straw which broke the camels back... What relics reside of that poor species?
And the Mystery of Planet Ergo in the Nemo system, a once oil rich ocean planet (until the Empire took all the oil) the mystery being how the oil, byproduct of organic life, got there as it is barren with no native life forms and no fossil record discovered as yet, the seas are as lifeless as the orbiting Asteroid around the planet named the Space Whale due to its unusual appearance... Was there once life on Ergo? Was it forced to leave having consumed the local biodiversity causing irreparable ecosystem collapse? Is that asteroid a purposely placed calling card of whatever the species that moved on was... and do they now reside in the clouds of Crusader now known as the Stormwhale...?
So hopefully you're right, there should be a bunch of archaeology beyond just these examples, too!
