Novels like Quest for the Marble of Many realities

All share LitRPG and Progression

Unlucky Druid Jack
4.44
Also Portal Fantasy / Isekai and Sci-fi
Chaotic Craftsman Worships The Cube
4.60
Also GameLit and Portal Fantasy / Isekai
Taming Destiny - a Tamer Class isekai/portal survival fantasy.
4.46
Also Adventure and GameLit
Orphan - Book One Complete!
4.57
Also GameLit and Sci-fi
Rise Of The Worthy
4.48
Also GameLit and Portal Fantasy / Isekai
Conduits
4.54
Also Action and Portal Fantasy / Isekai
Markets and Multiverses (A Serial Transmigration LitRPG)
4.55
Also GameLit and Portal Fantasy / Isekai
Riftside
4.35
Also GameLit and Portal Fantasy / Isekai
Explorer of Edregon (Book 5 Complete!)
4.55
Also GameLit and Portal Fantasy / Isekai
Nuclear Son
4.49
Also GameLit and Portal Fantasy / Isekai
Gamebreaker
4.35
Also GameLit and Portal Fantasy / Isekai
Divine Necromancer
4.39
Also GameLit and Portal Fantasy / Isekai