The Humble Store currently has a Cyan bundle:
https://www.humblebundle.com/games/myst-more-bundle I have tested all 11 games (Myst 2021 not included) on Windows 10 and the results are below:
Myst: Masterpiece Edition: The game is bundled with a ScummVM version that won't run without Steam. Just use another version of ScummVM and you are good to go.
Riven: The Sequel to MYST: Unlike Myst, the game is bundled with a ScummVM version that will run without Steam, out of the box.
Myst III: Exile: The game is bundled with ResidualVM and will work without Steam, out of the box.
Myst IV: Revelation: The game will run without Steam, out of the box (the executable can be found inside the bin folder).
URU: Complete Chronicles: The game will run without Steam, out of the box.
Myst V: End of Ages: The game will run without Steam, out of the box.
realMyst: Masterpiece Edition: As AB2012 mentioned above, the game will run without Steam, out of the box.
Obduction: The game will run without Steam, out of the box.
Cosmic Osmo and the World Beyond the Mackerel: I couldn't get the game to run without Steam.
The Manhole: Masterpiece Edition: I couldn't get the game to run without Steam (Note: ScummVM is not compatible with this version of Manhole).
Spelunx and the Caves of Mr. Seudo: The game will run without Steam, out of the box.