Games like Idiom
Games like Idiom include Black Myth: Wukong, Kingdom Rush - Tower Defense, Kingdom Rush Vengeance - Tower Defense, Mount & Blade II: Bannerlord, and Tails of Iron. We matched them by the tags players give Idiom on Steam (Strategy, Action, Action-Adventure, Action RPG, and 2D): closest matches first, and among equally close ones the better-known games.

Black Myth: Wukong
Shared: Action · Action RPG · Action-Adventure

Kingdom Rush - Tower Defense
Shared: Strategy · 2D · Action

Kingdom Rush Vengeance - Tower Defense
Shared: Strategy · 2D · Singleplayer

Mount & Blade II: Bannerlord
Shared: Strategy · Medieval · Action

Tails of Iron
Shared: Action RPG · 2D · Action-Adventure

God of War Ragnarök
Shared: Action · Action-Adventure · Action RPG

SANABI
Shared: Action · Story Rich · 2D

Crimson Desert Enhanced
Shared: Action · Singleplayer · Action-Adventure

Ghost of Tsushima DIRECTOR'S CUT
Shared: Action · Story Rich · Singleplayer

Dragon's Dogma 2
Shared: Action RPG · Action · Singleplayer

Kingdom Rush Origins - Tower Defense
Shared: Strategy · 2D · Singleplayer

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

FINAL FANTASY VII REMAKE INTERGRADE
Shared: Action RPG · Action-Adventure · Action

Kingdom Come: Deliverance II
Shared: Medieval · Action · Story Rich

Like a Dragon Gaiden: The Man Who Erased His Name
Shared: Action · Action RPG · Action-Adventure

Mount & Blade: Warband
Shared: Strategy · Medieval · Action

Marvel's Guardians of the Galaxy
Shared: Action-Adventure · Action · Story Rich

Assassin's Creed® Origins
Shared: Action-Adventure · Action · Singleplayer

FINAL FANTASY VII REBIRTH
Shared: Action · Action RPG · Action-Adventure

Marvel’s Spider-Man Remastered
Shared: Action · Action-Adventure · Story Rich

Tomb Raider Game of the Year
Shared: Action · Story Rich · Singleplayer

STAR WARS Jedi: Survivor™
Shared: Action · Singleplayer · Action-Adventure

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

God of War
Shared: Action · Story Rich · Singleplayer