Games like Hell's Handbook
Games like Hell's Handbook include Limbus Company, Poppy Playtime, Cyber Manhunt 2: New World - The Hacking Simulator, Firework, and The Painscreek Killings. We matched them by the tags players give Hell's Handbook on Steam (Strategy, Puzzle, Strategy RPG, Turn-Based Tactics, and Hand-drawn): closest matches first, and among equally close ones the better-known games.

Limbus Company
Shared: Turn-Based Tactics · Strategy · Lore-Rich

Poppy Playtime
Shared: Puzzle · Horror · Free to Play

Cyber Manhunt 2: New World - The Hacking Simulator
Shared: Puzzle · Detective · Dark Humor

Firework
Shared: Puzzle · Horror · Hand-drawn

The Painscreek Killings
Shared: Puzzle · Detective · Investigation

Cube Escape Collection
Shared: Puzzle · Horror · Mystery

Strange Horticulture
Shared: Puzzle · Detective · Mystery

We Were Here
Shared: Puzzle · Horror · Free to Play

Sally Face - Episode One
Shared: Puzzle · Horror · Hand-drawn

Tactical Breach Wizards
Shared: Puzzle · Turn-Based Tactics · Strategy RPG

Murders on the Yangtze River
Shared: Puzzle · Detective · Mystery

Mewgenics
Shared: Turn-Based Tactics · Dark Humor · Strategy

Warhammer 40,000: Chaos Gate - Daemonhunters
Shared: Strategy RPG · Turn-Based Tactics · Strategy

Into the Breach
Shared: Strategy · Turn-Based Tactics · Puzzle

Bendy and the Ink Machine
Shared: Puzzle · Horror · Strategy

Yu-Gi-Oh! Master Duel
Shared: Strategy · Turn-Based Tactics · Free to Play

Unheard - Voices of Crime
Shared: Puzzle · Detective · Mystery

The Case of the Golden Idol
Shared: Puzzle · Detective · Investigation

Ultimate Custom Night
Shared: Strategy · Horror · Free to Play

Danganronpa: Trigger Happy Havoc
Shared: Detective · Mystery · Puzzle

The Séance of Blake Manor
Shared: Puzzle · Detective · Mystery

Dupery: A Game of Solo Deduction
Shared: Strategy · Puzzle · Turn-Based Tactics

Inscryption
Shared: Puzzle · Strategy · Horror

Buckshot Roulette
Shared: Strategy · Horror · Puzzle