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