Games like The Necronomicon
Games like The Necronomicon include Bloons TD 6, Mirror 2: Project X, Florence, Where Winds Meet, and Monument Valley. We matched them by the tags players give The Necronomicon on Steam (Strategy, Adventure, Singleplayer, Casual, and Action-Adventure): closest matches first, and among equally close ones the better-known games.

Bloons TD 6
Shared: Strategy · Singleplayer · Casual

Mirror 2: Project X
Shared: 3D · Singleplayer · Interactive Fiction

Florence
Shared: Adventure · Casual · Singleplayer

Where Winds Meet
Shared: Singleplayer · Adventure · Action-Adventure

Monument Valley
Shared: Adventure · Singleplayer · Casual

Kingdom Rush - Tower Defense
Shared: Strategy · Singleplayer · Casual

Plants vs. Zombies GOTY Edition
Shared: Strategy · Singleplayer · Casual

Totally Accurate Battle Simulator
Shared: Strategy · Singleplayer · Adventure

Moncage
Shared: Casual · Singleplayer · Adventure

Plague Inc: Evolved
Shared: Strategy · Singleplayer · Casual

Rise of the Tomb Raider™
Shared: Adventure · Singleplayer · Action-Adventure

Idle Champions of the Forgotten Realms
Shared: Strategy · Adventure · Singleplayer

The Scroll of Taiwu : Beyond The Dome
Shared: Strategy · Singleplayer · Adventure

A Plague Tale: Requiem
Shared: Adventure · Action-Adventure · Interactive Fiction

Kingdom Rush Origins - Tower Defense
Shared: Strategy · Singleplayer · Casual

Tomb Raider Game of the Year
Shared: Adventure · Singleplayer · Action-Adventure

Game Dev Tycoon
Shared: Strategy · Casual · Singleplayer

Sultan's Game
Shared: Singleplayer · Strategy · Adventure

Home Behind
Shared: Adventure · Strategy · Casual

Slime Rancher 2
Shared: Singleplayer · Adventure · Casual

To the Moon
Shared: Adventure · Singleplayer · Interactive Fiction

Frankenstein: Master of Death
Shared: Casual · Adventure · Hidden Object

Caster
Shared: Adventure · Strategy · Casual

Rock 'N' Roll Defense
Shared: Strategy · Casual · Adventure