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