Soulmate

Tony Stark
It's smaller and on the upper right arm.

Stephen Strange
It's smaller and on the upper left arm.

Pepper Potts
Left pointing finger

Bucky Barnes
On their left collarbone

Steve Rogers
On the right hand and on their palm

Sam Wilson
On their left wirst

Rhodey
Right collarbone

Peter Quill
There on top of her left wrist

Gamora
On the same part of the leg like Peter Quill's pic, it's in the right leg

Peter Parker
Right pointing finger

Pietro Maximoff
On the right pinkies

Wanda Maximoff
On the left hand and on their palm

Natasha Romanoff
On their back on their left wing