Intrepid Merchant: A vital part of the interstellar economy outside the stargate network. Of course, given the power required to accelerate even a small bit of matter to a noticeable percentage of lightspeed such merchants generally trade more in data than material goods, selling licenses or fabricating the goods in-system from an unclaimed asteroid or too.
In the more trafficked unlinked worlds, trade tends to be dominated by mercantile cartels, guilds, or clans of assorted origin. Small “tramp” traders just can’t match their volume. Meanwhile, in the network laser transmissions through the stargates can transfer all the data any planet needs and shipping materials becomes economically feasible.