1Quick Transmigration

Sort of QT
Game creator is killed by his character and becomes a part of the game. After finishing the game he goes back to reality. Because of something he meets his character again and they get put into another game.

"Complete"
MC transmigrated after he died and is permanently locked by the system to return to the world as a different male character each time to target a different male host. He doesn't usually stay after the mission, however at the end he decids to go back to experience a happy ending with each different host.

"Complete"
Single Story
Villain has a system, and ends up raising the protagonist. The protagonist gains an ability that allows him to see the villains name even when he is disguised, which helps the protagonist fall for him.

MC was so close to becoming an immortal. Before he could receive an official certificate, he had to complete a task. His objective was to travel to different worlds and save the same target. However, in the first world, the target directly kills him.

MC is in an accident and ends up with a villain system. He goes to different worlds where to protagonist is the same person. He discovers that he was originally a system who was reincarnated and that the protagonist was his host who fell in love with him.