Here is the full list of all 50 Suicide Squad: Kill the Justice League achievements.
Reach Squad Level 50
Complete 100 Support Squad Contracts
Equip 3 pieces of the Tier 3 Infamy Set
Complete an Incursion Mission at Mastery level 20
Complete an Incursion Mission at Mastery level 15
Equip 3 pieces of the Tier 2 Infamy Set
Complete an Incursion Mission at Mastery level 10
Solve 21 of Riddler's Riddles
Complete 50 Support Squad Contracts
Solve 5 of Riddler's Riddles
Collect 40 Riddler Trophies
Begin the Batman Experience
Reach Max Level with Deadshot
Defeat 10 Raising Hell Hit Squads
Complete an Incursion Mission at Mastery level 5
Reach Max Level with Harley Quinn
Unlock a Villain Synergy
Equip 3 pieces of the Tier 1 Infamy Set
Get Poison Ivy to Supercharge the Affliction on a piece of gear
Get Toyman to Elite a piece of gear
Reach Max Level with Captain Boomerang
Complete the final Toyman Support Squad Mission
Complete your first Incursion Mission
Complete the final Poison Ivy Support Squad Mission
Reach Max Level with King Shark
Kill The Collector of Worlds
Achieve 39 Stars in Riddler AR Challenges
Complete the final Lex Luthor Support Squad Mission
Complete the final Gizmo Support Squad Mission
Complete the final Hack Support Squad Mission
Kill The Man of Steel
Complete the final Penguin Support Squad Mission
Kill The World's Greatest Detective
Achieve 26 Stars in Riddler AR Challenges
Kill The Green Lantern
Reach Level 10 with any Squad Member
Complete the final Rick Flag Support Squad Mission
Rescue Lex Luthor
Kill The Fastest Man Alive
Get Penguin to overhaul a piece of gear
Achieve 13 Stars in Riddler AR Challenges
Destroy the Behemoth
Fully complete the Combat Flair checklist 5 times (Single Player Sessions Only)
Recruit your second Support Squad member
Collect 10 Riddler Trophies
Escape plan gone wrong
Recruit your first Support Squad member
Survive the Batman Experience
Steal something useful from the Hall of Justice
What the hell just happened?