Here is the full list of all 37 Rebel Galaxy achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Become neutral to pirate factions
Break 10 blockades
Complete the main campaign
Find the Face of Gozu
Shoot down 500 torpedoes
Find an Antimatter Speck
Destroy 2,500 Fighter-Class Craft
Reach a Net Worth of 50 Million Credits
Purchase a Dreadnaught-class ship
Destroy 1,000 Capital-Class Craft
Find a Progenitor Shard
Collect 100 bounties
Purchase a Destroyer-class ship
Reach a Net Worth of 5 Million Credits
Successfully bribe a Militia official
Mine 50 asteroids using a Fault Tracker
Hack 10 transponders successfully
Join the Mercenaries' Guild
Jump out of the first solar system
Complete 50 missions from the mission board
Reach rank 5 in any Guild
Gather 200 objects with a tractor beam
Become friendly to the Militia
Salvage 50 Containers
Pirate a merchant
Rescue 20 merchants
Destroy 100 Capital-Class Craft
Kill 1 Pirate Lord
Break 1 blockade
Join the Merchant's Guild
Destroy 250 Fighter-Class Craft
Woke Trell
Purchase a new ship
Collect 10 bounties
Hire a mercenary
Trade with a Merchant while in flight
Kill 20 Pirate Lords