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