Regression #1

ML Regressed; is a Guideverse that is MxF ; FL Reincarnated/Transmigrated

He regresses in time, but in fact it's to another parallel timeline; builds a harem [not big in the storyline]. Spoilers tell me that when he saves this timeline, he will go back to the previous timeline with the girls to save that one, then live out his life in the forest with his harem.

Kick-ass FL ; ML is changing as we go.

FL is pulled into a novel and has to complete it correctly in order to return, but the ML messed the ending up somehow and the two are sent back to right after the FL's clan was destroyed, with her being the sole survivor. The novel is a mess, and she has been made the Protagonist and the ML is a variable, but she will do anything to save him even if the book assigned her a new ML.

This one is an interesting Regression; He became a constellation, but was killed. Since he was human before, Hades pulls his soul back and strikes a deal with him. Time for humans and such were rolled back to the day he awakened, but the Constellations remember his previous Constellation self that had been killed. None of them the wiser that it is in fact him returned, besides Hades.