Novels like The Null Mage

All share LitRPG and Progression

Divine Necromancer

4.39

Also GameLit and Portal Fantasy / Isekai

Explorer of Edregon (Book 5 Complete!)

4.55

Also High Fantasy and GameLit

The Four Treasures Saga

4.59

Also GameLit and Portal Fantasy / Isekai

Taming Destiny - a Tamer Class isekai/portal survival fantasy.

4.46

Also Male Lead and GameLit

Triple Strength

4.46

Also GameLit and High Fantasy

Penitent (Stubbed)

4.65

Also GameLit and Portal Fantasy / Isekai

Markets and Multiverses (A Serial Transmigration LitRPG)

4.55

Also GameLit and Portal Fantasy / Isekai

Journey to Veresavir

4.60

Also Magic and Portal Fantasy / Isekai

Overpowered Murderhobo

4.55

Also Portal Fantasy / Isekai and High Fantasy

First Date: Oblivion

4.46

Also Portal Fantasy / Isekai and High Fantasy

Skill Eater: A LitRPG Adventure

4.32

Also Portal Fantasy / Isekai and High Fantasy

The Archmage's Second Life as an Introvert

4.31

Also Portal Fantasy / Isekai and High Fantasy