Games like Harmony's Odyssey
Games like Harmony's Odyssey include The Last Campfire, Slime Rancher 2, Carto, Slime Rancher, and Donut County. We matched them by the tags players give Harmony's Odyssey on Steam (Puzzle, Adventure, Cute, Relaxing, and Family Friendly): closest matches first, and among equally close ones the better-known games.

The Last Campfire
Shared: Puzzle · Adventure · Cute

Slime Rancher 2
Shared: Cute · Relaxing · Adventure

Carto
Shared: Puzzle · Cute · Adventure

Slime Rancher
Shared: Cute · Adventure · Funny

Donut County
Shared: Puzzle · Cute · Adventure

Human Fall Flat
Shared: Puzzle · Adventure · Funny

Is This Seat Taken?
Shared: Puzzle · Cute · Relaxing

Pikuniku
Shared: Adventure · Puzzle · Cute

Portal 2
Shared: Puzzle · Puzzle Platformer · Funny

Webbed
Shared: Cute · Puzzle Platformer · Relaxing

A Hat in Time
Shared: Cute · Adventure · Female Protagonist

Untitled Goose Game
Shared: Puzzle · Cute · Funny

Tinykin
Shared: Cute · Puzzle · Family Friendly

TOEM: A Photo Adventure
Shared: Puzzle · Adventure · Cute

A Little to the Left
Shared: Puzzle · Relaxing · Cute

Assemble with Care
Shared: Puzzle · Relaxing · Female Protagonist

Monument Valley
Shared: Puzzle · Adventure · Relaxing

GRIS
Shared: Adventure · Female Protagonist · Relaxing

CATO: Buttered Cat
Shared: Cute · Adventure · Puzzle

Unpacking
Shared: Cute · Relaxing · Puzzle

Scribblenauts Unlimited
Shared: Puzzle · Adventure · Family Friendly

Chicory: A Colorful Tale
Shared: Adventure · Cute · Puzzle

Portal
Shared: Puzzle · Puzzle Platformer · Female Protagonist

The Pedestrian
Shared: Puzzle · Puzzle Platformer · Adventure