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