C'era una volta il West/BluRay

The specifications and extras of the Paramount releases are mostly identical across all markets, with just slight variations.

Once Upon A Time In The West
Label: Paramount Pictures
Release date: May 31, 2011
Region: A, B, C
Video: 2.35:1
Audio: English DD mono, English DTS-HD 5.1, Spanish DD mono, French DD mono, Portuguese DD mono
Subtitles: English, Spanish, French, Portuguese
Runtime: 165 min
Includes theatrical and restored version (but only 20 sec longer)
Buy now: From Amazon.com | Amazon.uk | Amazon.ca

50th Anniversary Edition - collectible book edition "The story of a masterpiece"
Region free
Release date: September 2nd, 2019
Audio: English; German; French
Subtitles: French, German, Dutch, Danish, Norwegian
SPECIAL FEATURES: Commentary with Contributions from Directors John Carpenter, John Milius & Alex Cox, Film Historians Sir Christopher Frayling & Dr. Sheldon Hall, and Cast & Crew; An Opera of Violence (29min); The Wages of Sin (20min); Something to do with Death (18min); Railroad: Revolutionising The West (6min); Locations Then & Now; Production Gallery; Theatrical Trailer
Buy now: From Amazon.co.uk | From Amazon.com

Release date: January 1, 2018
Re-release Steelbook, region free
Label: Paramount
Probably identical to below edition
From official description: " Special Features Commentary with Contributions from Directors John Carpenter, John Milius & Alex Cox, Film Historians Sir Christopher Frayling & Dr. Sheldon Hall and Cast & Crew; An Opera of Violence (29min); The Wages of Sin (20min); Something to do with Death (18min); Railroad: Revolutionising The West (6min); The West Locations Then & Now; Production Gallery; Theatrical Trailer - HD"
Buy now: From Amazon.co.uk | From Amazon.fr

Label: Paramount / Universal (Germany and Austria)
Release date: December 5, 2019
Limited Digibook
in Switzerland from a different distributor
tbc if technical specs differ from previous releases. The press release says "original version" but that doesn't mean much. Likely same as UK September 2019 release.
Buy now: From Amazon.de | From Amazon.pl

Label: Paramount
Release date: December 6, 2018
Limited Steelbook re-release
Audio: German DD mono, English DD mono, English DTS-HD 5.1, Spanish DD mono, French DD mono
Subtitles: German, English, Spanish, French, Danish, Dutch, Norwegian, Swedish, Finnish
Runtime: 165 min 24 s (theatrical version); 166 min 1 s (restored version; includes 17 s restoration information at the beginning)
Buy now: From Amazon.de

Spiel mir das Lied vom Tod
Label: Paramount Home Entertainment
Release date: June 9, 2011)
Region: A, B, C
Video: 2.35:1
Audio: German DD mono, English DD mono, English DTS-HD 5.1, Spanish DD mono, French DD mono
Subtitles: German, English, Spanish, French, Danish, Dutch, Norwegian, Swedish, Finnish
Runtime: 165 min
Includes theatrical and restored version (but only 20 sec longer)
Buy now: From Amazon.de | Amazon.it | Amazon.es | From Amazon.se | From Amazon.nl | From Amazon.pl

Exclusive Limited Premium Edition
Label: Paramount Home Entertainment
Release date: June 9, 2011
Includes theatrical and restored versions
Includes the regular BluRay (see above) as a Steelbook, comes in a wooden box with golden closures and the title of the film embossed in gold. Plus three postcards, a silver harmonica with the title of the film engraved and in a leather pouch, a zippo lighter with gold dust optics, a 20 page booklet; a color A2 poster;
Buy now: From Amazon.de

Cofanetto Sergio Leone - La Trilogia Del Tempo includes C'era una volta il West, Giù la testa and Once Upon a Time in America.
Label: Eagle Pictures
Release date: November 17, 2021
Steelbook, 3 BluRays, with 30 page booklet (containing screenplay excerpts, still images and more)
Details tbc
Buy now: From Amazon.it | From Amazon.pl

Label: Eagle Pictures
Release date: December 15, 2017
Sergio Leone box (7 movies: Dollars trilogy, Duck you sucker, America, Colossus of Rhodes, Once Upon a time in the West)
Limited edition, with numbered postcards; also released on DVD
Buy now: From Amazon.it | From Amazon.de

Release date: December 2013
Label: O1 Distribution / Rai
Details: This is the Paramount restoration; Extras: only the trailer. No English language options
Audio: Italian mono and 5.1 DTS-HD MA
Subtitles: Italian
Region B
Buy now: From Amazon.it

Release date: October 23, 2019
Label: Paramount
Édition 50ème Anniversaire, likely same as UK release - includes booklet (in French)
Buy now: From Amazon.fr | From Amazon.se | From Amazon.nl

Label: November 5, 2014
Sergio Leone: Le maître du Western (7 disc) set
Label: MGM/UA and StudioCanal
Contains: all of Leone's westerns, including both Nobody movies (A Genius... only on DVD!!), and Duck You Sucker for the first time in HD
Buy now: From Amazon.fr | Amazon.it | Amazon.es | Amazon.de

Il était une fois dans l'ouest
Paramount Home Entertainment (June 16, 2011)
Combo with DVD
Region: A,B,C
Video: 2.35:1 anamorphic
Audio: French, English, German, Spanish
Subtitles: German, English, Spanish, French, Danish, Dutch, Norwegian, Swedish, Finnish
Runtime: 165 min
Includes theatrical and restored version (but only 20 sec longer)
Buy now: From Amazon.fr | Amazon.it | Amazon.es

Release date: September 18, 2019
Digibook release; texts in English
All regions
Label: Paramount Pictures
Audio: German, English, French, Spanish, Italian
Subtitles: English, Spanish, French, German, Dutch, Danish, Swedish, Norwegian, Finnish
Buy now: From Amazon.es

Hasta que llegó su hora
Label: Paramount Home Entertainment
Release date: June 29, 2011
Region: B
Video: 2.35:1
Audio: Spanish, French, English, German
Subtitles: Spanish, Portuguese, German, English, French, Greek, Dutch, Norwegian, Swedish, Finnish, Polish, Hungarian, Romanian, Turkish, Arabic
Runtime: 165 min
Buy now: From Amazon.co.uk | Amazon.es