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