Artificers can make Lightsabers, Gormak Crystals (for the Nightmare Pilgrim boss), Relics, Generator/Focus offhands, and dyes. The mods they make are Crystals and Hilts (not all mods).
Since the Explosive Conflict operation was introduced in Patch 1.2, Artificers can make end-game gear via Reverse Engineering. Hilts from Operations gear can be ripped out and RE'd for a chance at learning the schematic, and Relics can similarly be RE'd and learned.
A few low-level crystal schematics come from Investigation, and four Lightsaber schematics come from Treasure Hunting. The Magenta crystal schematics mostly come from world bossesThe Magenta crystal schematics mostly come from world bosses as another answer notes, with Orange crystal schematics also dropping from the Primal Destroyer. Some Rakata (level 58, tier 25) enhancement schematics drop rarely in Operations. Finally, the Gormak Crystal schematic is available from the Level 50 daily zone vendors; that's it apart from what you learn from the artifice trainer.