Games like YGGDRASILL
Games like YGGDRASILL include Russian Life Simulator, Mountain, Cookie Clicker, Reus, and Game Dev Tycoon. We matched them by the tags players give YGGDRASILL on Steam (Simulation, Incremental, 2D, Singleplayer, and Casual): closest matches first, and among equally close ones the better-known games.

Russian Life Simulator
Shared: Simulation · Incremental · Singleplayer

Mountain
Shared: Simulation · Casual · Singleplayer

Cookie Clicker
Shared: Incremental · Casual · Indie

Reus
Shared: Simulation · God Game · Singleplayer

Game Dev Tycoon
Shared: Simulation · Casual · Singleplayer

Papers, Please
Shared: Simulation · Singleplayer · Indie

Plague Inc: Evolved
Shared: Simulation · Singleplayer · Casual

House Flipper
Shared: Simulation · Singleplayer · Building

People Playground
Shared: 2D · Simulation · Singleplayer

Touhou Mystia's Izakaya
Shared: Simulation · Casual · Faith

A Game About Feeding A Black Hole
Shared: Incremental · Casual · Simulation

Potion Craft: Alchemist Simulator
Shared: Simulation · Singleplayer · 2D

Equilinox
Shared: Simulation · Casual · Singleplayer

Nodebuster
Shared: Incremental · Simulation · Casual

911 Operator
Shared: Simulation · Singleplayer · Casual

Click Mage
Shared: Simulation · Incremental · Casual

Garry's Mod
Shared: Casual · Building · Singleplayer

Project Highrise
Shared: Simulation · Singleplayer · 2D

Click the Button
Shared: Incremental · Simulation · Casual

Two Point Hospital
Shared: Simulation · Singleplayer · Building

Oxygen Not Included
Shared: Singleplayer · 2D · Building

Shelldiver
Shared: Incremental · Casual · Simulation

Gas Station Simulator
Shared: Simulation · Singleplayer · Casual

Cities: Skylines
Shared: Simulation · Building · Singleplayer