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