Alternatives to Stockfish Chess
The world's strongest engine, free and open source. If that's not for you - or you want to try something different - here are apps that overlap on features and use cases.

Forward Chess
Forward Chess, LLC
Interactive chess ebook reader with embedded engine.
Free
4.8Web · iOS · Android

Scid vs. PC
Steven Atkinson and contributors
Open-source database and analysis powerhouse.
Free
Windows · macOS · Linux

Arena Chess GUI
Martin Blume
Veteran free GUI for running 250+ chess engines.
Free
Windows · Linux

Chess.com
Chess.com, LLC
The default home of online chess.
Free · from $4.17/mo
4.5Web · iOS · Android

Chess King Learn
Chess King (CHESSQUEEN INC, ex-Convekta)
Huge Convekta course catalog in one app.
Free
4.8Web · iOS · Android

Shredder Chess
Stefan Meyer-Kahlen
A classic standalone chess engine for offline play.
From $7.99 one-time
iOS · Android · macOS

Chessnut Air
Pendo Technology Ltd. (Chessnut)
Affordable electronic board with multi-app support.
From $249.99 one-time
2.6iOS · Android · Windows

Aimchess
Aimchess (Chess.com group)
AI that finds your chess weaknesses and drills them.
Free · from $7.99/mo
4.1Web · iOS · Android