Games like Idle Campaign
Games like Idle Campaign include Idle Champions of the Forgotten Realms, Cookie Clicker, Dragon Cliff, Shelldiver, and Nodebuster. We matched them by the tags players give Idle Campaign on Steam (Free to Play, Idler, Incremental, Management, and Collectathon): closest matches first, and among equally close ones the better-known games.

Idle Champions of the Forgotten Realms
Shared: Free to Play · Idler · Incremental

Cookie Clicker
Shared: Idler · Incremental · Management

Dragon Cliff
Shared: Idler · Incremental · Strategy

Shelldiver
Shared: Incremental · Management · Idler

Nodebuster
Shared: Incremental · Idler · Strategy

Loot Loop
Shared: Incremental · Idler · Management

Firestone – Idle Clicker Online RPG
Shared: Idler · Incremental · Auto Battler

Digseum
Shared: Incremental · Idler · Management

Chef Knight
Shared: Incremental · Management · Idler

Your Chronicle
Shared: Idler · Incremental · Free to Play

Tower Wizard
Shared: Idler · Incremental · Resource Management

Keep on Mining!
Shared: Idler · Incremental · Casual

Bills Must Be Paid
Shared: Incremental · Idler · Strategy

(the) Gnorp Apologue
Shared: Idler · Incremental · Management

A Game About Feeding A Black Hole
Shared: Incremental · Idler · Strategy

Kiwi Clicker - Juiced Up
Shared: Incremental · Idler · Collectathon

Scritchy Scratchy
Shared: Incremental · Idler · Resource Management

Book of Yog Idle RPG
Shared: Auto Battler · Loot · Hack and Slash

Incredicer
Shared: Idler · Incremental · Strategy

Path of Idle: Old Gods Rising
Shared: Idler · Strategy · RPG

Click the Button
Shared: Incremental · Idler · Collectathon

Zero Stress King: Idle Defense
Shared: Idler · Incremental · Auto Battler

Incremental Epic Hero 2
Shared: Idler · Auto Battler · Management

Swag and Sorcery
Shared: Management · Incremental · RPG