Games like Grief
Games like Grief include What Remains of Edith Finch, Firewatch, Layers of Fear (2016), SOMA, and Outer Wilds. We matched them by the tags players give Grief on Steam (Exploration, Hidden Object, Puzzle, Walking Simulator, and First-Person): closest matches first, and among equally close ones the better-known games.

What Remains of Edith Finch
Shared: Walking Simulator · Exploration · Story Rich

Firewatch
Shared: Walking Simulator · Exploration · Story Rich

Layers of Fear (2016)
Shared: Horror · Walking Simulator · First-Person

SOMA
Shared: Horror · Exploration · Story Rich

Outer Wilds
Shared: Exploration · Story Rich · Puzzle

Amnesia: A Machine For Pigs
Shared: Walking Simulator · Horror · Exploration

INFRA
Shared: Exploration · Puzzle · Walking Simulator

The Exit 8
Shared: Exploration · Puzzle · Walking Simulator

Poppy Playtime
Shared: Puzzle · Horror · First-Person

Amnesia: Rebirth
Shared: Puzzle · First-Person · Exploration

Sally Face - Episode One
Shared: Story Rich · Puzzle · Horror

The Room 4: Old Sins
Shared: Puzzle · Hidden Object · Exploration

Still Wakes the Deep
Shared: Horror · First-Person · Walking Simulator

The Witness
Shared: Exploration · Puzzle · First-Person

Killer Frequency
Shared: Puzzle · Horror · First-Person

Bendy and the Ink Machine
Shared: Puzzle · First-Person · Horror

Platform 8
Shared: Walking Simulator · Puzzle · Hidden Object

The Room Two
Shared: Puzzle · Hidden Object · Horror

Little Nightmares II
Shared: Puzzle · Horror · Adventure

Inside the Backrooms
Shared: Puzzle · Horror · Exploration

The Beginner's Guide
Shared: Walking Simulator · Story Rich · First-Person

Scanner Sombre
Shared: Exploration · Walking Simulator · Horror

Gone Home
Shared: Exploration · Walking Simulator · First-Person

The Room
Shared: Puzzle · Hidden Object · Horror