The Setup
Large map, 12 random civilizations.
The Expedition: the backdrop

In 2253, the milky way galaxy had settled to roughly this configuration.

Blue: Terran Alliance
Purple: Yor
Red: Drengin Empire
Green: Torians
Yellow: Arceans
Cyan: Altarians
With the other major civilizations being located in the vicinity.
Back in the year 2178, humans invented hyperdrive which made per-ship faster than travel possible. This technology replaced the ancient stargate technology that the Arceans and Drengin utilized. It is that technology that allowed for so much of the Orion Spur to be explored.
I talk a lot about Orion's Spur in the various Star Control journals (the GalCiv universe is different from the various universes in the Star Control multiverse but that's a different discussion). The main point though is that this is a massive, massive area of space.
In 2245, Hypergates were invented and they accelerate hyperdrive in a direct line between two hypergates.
The expedition involves exploring the Perseus Arm of the galaxy. According to the Iconians, the Precursors wars took place primarily in this area of the galaxy about a half million years ago.
The distance between Orion's Spur and the Perseus Arm is far too far to reach even with Hyperdrive. But with Hyperdrive accelerated by Hypergates it might be possible.

The expedition's mission is to go into the outermost corner of Orion's Spur, secure the area and attempt to gather the resources to build the first half of a "Super" hypergate, the second being one that will eventually be in the Perseus Arm. It will take decades, even at the fastest "cheesed" unmanned Hypdrive ship to reach the Perseus arm to set up the other half of the Hypergate chain.
END OF CANON
From here on out, I'm going to focus on this particular game played with GalCiv III v3.81. I have downloaded a bunch of alien civilizations from Steam workshop so I have no idea who I'll be running into.

This particular map has 4 clusters of stars with a 5th mini cluster.
Early meetings
The Feyrin Conclave is the first civilization I run into. This mod was created by Dragon Mom.

Next up are the Mu'Kay from Star Control: Origins (Heroes of Star Control DLC).

Next up, Other Joe from the Angry Joe Show!

Next up:

The Dalek from Dr. Who I presume. Mod made by Omnibus.
Next up:
The Centauri Republic. Mod made by Galacti-Chron.

FAST FORWARD

I had hoped we would be friends with the Daleks. But they just want to "exterminate" us.