When you unlock the first terminal, you gain the ability to buy/sell Raw Wood, Stone, Coal, Copper Ore, Iron Ore, and Raw Fish. The second terminal adds Crude Oil, and the third adds Alien Artifact.
Additional research unlocks the ability to buy (but not sell) Copper Plate, Iron Plate, Steel Plate, Electronic Circuit, Advanced Circuit, and Processing Unit.
You can also unlock the ability to buy electric power.
Since I did not intend to completely replace traditional factories, I didn't add the ability to buy more complex items. Originally I was only going to do raw materials, but I loosened it up a bit because I found the game felt too vanilla with only raw stuff.
In the future, if there is interest, I may add support from raw materials associated with other mods.
I hope this answers your question.