Games like The Idle
Games like The Idle include Cookie Clicker, Scritchy Scratchy, Shelldiver, Digseum, and Fortune Mill. We matched them by the tags players give The Idle on Steam (Idler, Incremental, Sandbox, Management, and Text-Based): closest matches first, and among equally close ones the better-known games.

Cookie Clicker
Shared: Idler · Incremental · Management

Scritchy Scratchy
Shared: Incremental · Idler · Management

Shelldiver
Shared: Incremental · Idler · Management

Digseum
Shared: Incremental · Idler · Management

Fortune Mill
Shared: Idler · Incremental · Economy

Planet Coaster
Shared: Sandbox · Management · Simulation

Potion Craft: Alchemist Simulator
Shared: Management · Relaxing · Simulation

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

Nodebuster
Shared: Incremental · Idler · Management

Cities: Skylines
Shared: Management · Sandbox · Simulation

Cities: Skylines II
Shared: Sandbox · Management · Simulation

Planet Zoo
Shared: Management · Sandbox · Simulation

Kingdoms and Castles
Shared: Management · Sandbox · Simulation

Big Ambitions
Shared: Management · Economy · Sandbox

Foundation
Shared: Sandbox · Management · Simulation

Keep on Mining!
Shared: Idler · Incremental · Relaxing

Rusty's Retirement
Shared: Idler · Management · Relaxing

Tiny Pasture
Shared: Idler · Incremental · Management

WorldBox - God Simulator
Shared: Sandbox · Simulation · God Game

Tower Wizard
Shared: Idler · Incremental · Resource Management

News Tower
Shared: Management · Sandbox · Simulation

Lyca
Shared: Incremental · Idler · Management