Aven Colony

You’ll finish dozens of trade contracts simply by completing the trade assignments given to you in the story missions, but there’s a way to grind them out quickly.

Once you have a well-developed colony you’ll receive trade deals where you import consumer goods like helper robots in exchange for 15 nanites or so. You should being creating a steady supply of nanites by this point, so build as many trade hubs as you need to accept these trade deals.

These deals are nice because they’re just a short trip to the colony ship and back - making them fast to complete - and they repeat automatically. Since each repetition counts as a separate completed contract you can rack up progress towards this achievement pretty quickly. As an added bonus, you can sell these consumer goods in your retail centers (found in the Services section) and boost the morale of your colony.

I managed to get about 20 completed deals at the end of a mission in no time at all by having two trade hubs import consumer goods non-stop on 8x game speed.