Here is the full list of all 70 Heat Signature achievements.
Talk to Fiasco after liberating every Stronghold
Completely eliminate a faction from the galaxy
Teleport to an airlock with the Glitcher's Tick
Break a ship with the Foundry Brick
Complete a Hijack mission in a Warzone
Rescue one of your own characters
Complete a Pacifist Clause
Complete a Mistake mission
Complete a Ghost Clause
Reflect a bullet with an emergency shield
Delete a Galaxy
Start a new galaxy
Kill someone with a Shortblade within 1 second of killing someone with a Longblade
Pass through a ship's vision undetected in the Sovereign Coldfire
Knock yourself out with a wrench you threw
Take someone out with a melee attack less than 0.5 seconds after Sidewinding
Acquire a keycard while Visiting
Be rescued from your captor by the Visitor
Use a second Visitor before the first returns you
Knock a Capture target through a window
Complete a Silence Clause
Complete an assassination mission without harming any other crew
Cause a sentry to shoot a guard by subverting it
Cause a guard with a subverted shield to shoot themselves
Complete a theft without being seen or harming anyone
Dock at a friendly station while on emergency fuel
Complete your personal mission
Save someone with the Offworld Angel
Complete an Audacious (or harder) mission
Complete an Assassinate mission without entering the ship
Complete an Enigma Clause
Cause a guard to shoot themselves by Swapping with them
Make it to a station after your pod has been destroyed
Board a ship without docking your pod
Complete a Bloodless Clause
Liberate a station
Complete a Hard (or harder) mission
Catch a Rescue target in your pod while they're suffocating in space
Deliver an assassination target alive
Complete a practice mission
Retire as a Living Legend
Find a unique item
Crash a shield
Retire Sader Fiasco
Rescue a friend's character
Find an item that belonged to a Steam friend's character