Basically, it's your name but with their last name.

Tony Stark (Iron Man): (Y/N) Stark

Steve Rogers (Captain America): (Y/N) Rogers

Bruce Banner (Hulk): (Y/N) Banner

Clint Barton (Hawkeye): (Y/N) Barton

Thor Odinson: (Y/N) Thorsdóttir

Pietro Maximoff (Quicksilver): (Y/N) Maximoff

Natasha Romanoff (Black Widow): (Y/N) Romanoff

Wanda Maximoff (Scarlet Witch): (Y/N) Maximoff

Helen Cho: (Y/N) Cho

Wade Wilson (Deadpool): (Y/N) Wilson

James Howlett\Logan (Wolverine): (Y/N) Howlett

Scott Summers (Cyclops): (Y/N) Summers

Alexander Summers (Havok): (Y/N) Summers

Jean Grey: (Y/N) Grey

Ororo Munroe (Storm): (Y/N) Monroe

Peter Parker (Spider-Man): (Y/N) Parker

Susan Storm (Invisible Woman): (Y/N) Storm

Reed Richards (Mr.Fantastic): (Y/N) Richards

Jonathan Storm (Human Torch): (Y/N) Storm

Loki Laufeyson: (Y/N) Lokisdóttir

Darren Cross (Yellowjacket): (Y/N) Cross

Arcade: (Y/N)

En Sabah Nur (Apocalypse): (Y/N) Nur

Scott Lang (Ant-Man): (Y/N)  Lang

Eric Lehnsherr (Magneto): (Y/N) Lehnsherr

Raven Darkhölme (Mystique): (Y/N) Darkhölme

Charles Xavier (Professor X): (Y/N) Xavier