Games like Gray Matter
Games like Gray Matter include Syberia, The Room, Syberia 3, The Room 4: Old Sins, and Tomb Raider Game of the Year. We matched them by the tags players give Gray Matter on Steam (Adventure, Point & Click, Female Protagonist, Casual, and Mystery): closest matches first, and among equally close ones the better-known games.

Syberia
Shared: Adventure · Point & Click · Female Protagonist

The Room
Shared: Point & Click · Mystery · Adventure

Syberia 3
Shared: Adventure · Point & Click · Female Protagonist

The Room 4: Old Sins
Shared: Point & Click · Adventure · Mystery

Tomb Raider Game of the Year
Shared: Adventure · Female Protagonist · Singleplayer

Rise of the Tomb Raider™
Shared: Adventure · Female Protagonist · Singleplayer

What Remains of Edith Finch
Shared: Adventure · Story Rich · Mystery

A Plague Tale: Innocence
Shared: Adventure · Female Protagonist · Story Rich

The Room Three
Shared: Adventure · Point & Click · Mystery

Outer Wilds
Shared: Adventure · Mystery · Story Rich

Firewatch
Shared: Adventure · Mystery · Story Rich

Syberia II
Shared: Adventure · Point & Click · Female Protagonist

The Room Two
Shared: Point & Click · Mystery · Adventure

Life is Strange: Before the Storm
Shared: Female Protagonist · Story Rich · Adventure

GRIS
Shared: Adventure · Female Protagonist · Great Soundtrack

The Witcher 3: Wild Hunt — Remastered
Shared: Adventure · Story Rich · Singleplayer

Chants of Sennaar
Shared: Adventure · Point & Click · Singleplayer

Servant of the Lake
Shared: Adventure · Point & Click · Puzzle

Sherlock Holmes: The Devil's Daughter
Shared: Adventure · Mystery · Story Rich

Broken Age
Shared: Adventure · Point & Click · Story Rich

Syberia: The World Before
Shared: Adventure · Point & Click · Female Protagonist

Boxes: Lost Fragments
Shared: Point & Click · Adventure · Mystery

Phoenix Wright: Ace Attorney Trilogy
Shared: Mystery · Story Rich · Adventure

Gorogoa
Shared: Point & Click · Singleplayer · Puzzle