I think my favorite artifact story is Pohl's
Heechee saga, exploring
Gateway station and trying to figure out the controls of the docked ships was really great scifi fun, and the interspersed chapters of the protagonist bickering with his software therapist made sure it wasn't dry on the human element side either. And there's always
Rendezvous with Rama of course.
SCE did this kind of stuff regularly by its very nature, I still want it back ...