I just read Going Back and Forth Between Earth and The Other World with Space Time Magic and I was hooked with the Idea of a person who travels between two world . Novel where Mc returns back to his former world with his power intact is also welcome . or Novel where Mc receives Cheat but isnt transported is also included ~!
The bounty hunter on royale roads fits the bill. Mc can travel back an forth between fantasy and modern world.
I Have a Mansion in the Post-apocalyptic World The empress's Gigolo There should be more, but these two are the only one that i can think of atm.
Kumo Desu ga, Nani ka? - At one point she becomes powerful enough to freely travel between worlds and return back to earth. But she only does it in the special holiday chapters for some silly shenanigans. Her work still mostly lies in the other world so she spends almost all of her time there.
All my classmate was summoned to another world except me or so the title and l'm back from another but nothing changed or so the title
My Entire Class Was Summoned to Another World except for Me Got left behind because the MC sits in the corner, thus missed by the summoning circle. Still got the cheats tho.