Currently found:
Rayman 1 and spin-offs:
http://s332.photobucket.com/user/Haruka ... n.jpg.html - A beta cartridge of Rayman 1, found by Haruka.
http://fc01.deviantart.net/fs71/f/2013/ ... 6c9ji1.png - Magician Artwork from Rayman CP
http://www.vintagecomputing.com/wp-cont ... _large.jpg - R1 Advertising
http://www.mobygames.com/game/maths-and ... Id,241020/ - EduRay Advertising
http://img89.imageshack.us/img89/8419/ybwx.png - EduRay artwork
http://fc07.deviantart.net/fs70/f/2013/ ... 6f8y8v.png - Lividstone CP
http://imagizer.imageshack.us/a/img32/5083/dap9.png - Premier Clics Activity artwork
http://imagizer.imageshack.us/a/img849/1447/u6j2.png - Premier Clics Activity artwork
http://imagizer.imageshack.us/a/img855/5272/ue0s.png - Premier Clics Activity artwork
http://imagizer.imageshack.us/a/img832/6871/uufu.png - Premier Clics Activity artwork
http://img826.imageshack.us/img826/728/ifgd.png - Magician Artwork
Rayman 2 and spin-offs:
http://games.sina.com.cn/newgames/9908/ ... 081111.jpg - Rayman 2 beta
http://games.sina.com.cn/newgames/9908/ ... 081112.jpg - Rayman 2 beta
http://games.sina.com.cn/newgames/9908/ ... 081109.jpg - Rayman 2 beta
http://games.sina.com.cn/newgames/9908/ ... 081110.jpg - Rayman 2 beta
http://oi41.tinypic.com/2hmzosp.jpg - A rare view of Foutch's back, caught by Shroobie.
http://aufonddelatelier.com/video%20gam ... yman01.jpg - Revolution Art
http://aufonddelatelier.com/video%20gam ... yman02.jpg - Revolution Art
http://aufonddelatelier.com/video%20gam ... yman03.jpg - Revolution Art
http://aufonddelatelier.com/video%20gam ... yman04.jpg - Revolution Art
http://raymanpc.com/forum/download/file ... &mode=view - R2 Promo Art
http://www.unseen64.net/wp-content/uplo ... 4_640w.jpg - R2 Beta Screencap
http://www.unseen64.net/wp-content/uplo ... 3_640w.jpg - R2 Beta Screencap
http://www.unseen64.net/wp-content/uplo ... 2_640w.jpg - R2 Beta Screencap
http://www.unseen64.net/wp-content/uplo ... 2_640w.jpg - R2 Beta Screencap
Rayman M and spin-offs:
http://rayman.bonusweb.cz/pok2_wantedra ... mage_6.jpg - Rayman Arena concept art
http://rayman.bonusweb.cz/pok2_wantedra ... mage_5.jpg - Rayman Arena concept art
http://rayman.bonusweb.cz/pok2_wantedra ... mage_4.jpg - Rayman Arena concept art
http://rayman.bonusweb.cz/pok2_wantedra ... mage_3.jpg - Rayman Arena concept art
http://i44.servimg.com/u/f44/12/34/73/40/tilypo10.jpg - Creepy Tily
Rayman 3 and spin-offs:
http://www.mhauss.com/HTML/book_01.htm - Rayman 3 artworks
http://img.jeuxvideopc.com/artwork/6692 ... voc-41.jpg - What appears to be one of the doctor's houses from Rayman 3.
http://2.bp.blogspot.com/_Xm9bSEenMsQ/T ... antasy.jpg - Rayman 3 concept?
http://2.bp.blogspot.com/_Xm9bSEenMsQ/T ... man+3D.jpg - Rayman 3 concept
http://www.afpa-creteil.org/alainB/03_ifrCreations.html - Rayman 3 textures
http://tofbourges.free.fr/BooK.htm#raymanIII_2 - Beta screens of Rayman 3
http://tinypic.com/view.php?pic=347xrty ... zHJx6h_uSo - Presumably Rayman 3 concept art
http://redacesmedia.com/#prettyPhoto[gallery1]/12/ - Art of Rayman 3 cover (have to highlight and copy paste, due to forum tags)
http://www.digitpress.com/images/e32k2/rayman3.jpg - R3 E3 2002
http://www.digitpress.com/images/e32k2/ ... racter.jpg - R3 E3 2002
http://www.digitpress.com/images/e32k2/ ... an_3_2.jpg - R3 E3 2002
http://www.digitpress.com/images/e32k2/ ... yman_3.jpg - R3 E3 2002
http://www.digitpress.com/images/e32k2/don/rayman3.jpg - R3 E3 2002
http://raymanpc.com/forum/download/file ... &mode=view - R3 Beta cap
http://25.media.tumblr.com/8358ec4b8425 ... 5_1280.jpg - R3 Artwork
http://24.media.tumblr.com/2cbbe2e0be20 ... 4_1280.jpg - R3 Artwork
http://25.media.tumblr.com/e80780e822a5 ... 3_1280.jpg - R3 Artwork
http://25.media.tumblr.com/6f3ed226db12 ... o2_500.jpg - R3 Artwork
http://24.media.tumblr.com/afe52a7200bd ... 1_1280.jpg - R3 Artwork
http://i.imgur.com/iWckkco.png - R3 Sticker
http://i.imgur.com/DW6GbOL.png - R3 Sticker
http://i.imgur.com/JcGD9wr.png - R3 Sticker
http://i.imgur.com/X09dij6.png - R3 Sticker
http://i.imgur.com/yMSes1v.png - R3 Sticker
http://i.imgur.com/xY9LnxG.png - R3 Sticker
Rayman Origins:
http://2.bp.blogspot.com/-dJ2k5x9f7A0/T ... 2%2529.jpg - Origins Concept Art
http://floony.blogspot.co.uk/ - Origins Concept Art
http://tinypic.com/view.php?pic=1ju7eo&s=5#.UzHJuqh_uSo - Origins Concept Art
http://mehdichatr.weebly.com/3d--video-game.html - Artworks for Origins and Rabbids
http://athanex.com/ - Origins and Legends Artwork
http://25.media.tumblr.com/tumblr_m7vei ... 2_1280.jpg - RO Artwork
http://24.media.tumblr.com/tumblr_m7vei ... 4_1280.jpg - RO Artwork
http://1.bp.blogspot.com/-bM5G4vWZM68/U ... outain.jpg - RO Artwork
http://omarsabrou.weebly.com/ubisoft-video-game.html - Origins and Rabbids
Rayman Legends:
http://cmessier.blogspot.de/search/labe ... %20LEGENDS - Rayman Legends Artwork
http://cmessier.blogspot.de/search/labe ... %20LEGENDS - Legends Artwork
https://fbcdn-sphotos-c-a.akamaihd.net/ ... 6234_n.jpg - RL Concept Art
http://kadwork.blogspot.co.uk/search?q=Rayman - Legends stuff
Rabbids:
http://i332.photobucket.com/albums/m353 ... 255875.jpg - Kinder Rabbids, from Haruka, could this put in Merch?
http://1.bp.blogspot.com/_Xm9bSEenMsQ/T ... sition.jpg - Rabbid Concept Art
http://4.bp.blogspot.com/_Xm9bSEenMsQ/T ... MMORAL.jpg - Rabbid Concept Art?
http://2.bp.blogspot.com/_Xm9bSEenMsQ/T ... /9noya.jpg - Rabbid Concept Art
http://i332.photobucket.com/albums/m353 ... rayman.jpg - Rabbid Concept Art, found by Haruka.
The Animated Series:
http://grandahu.pagesperso-orange.fr/book.html - RTAS concept art here
http://leonjoosen.com/portfolio/storyboards/ - RTAS storyboard
http://leonjoosen.com/portfolio/film-and-tv/ - RTAS Artwork
Other/Misc:
http://www.corbillart.com/Games.htm - Collection of artworks, check to see if there's anything particularly nice.
http://www.telegraph.co.uk/technology/v ... ml?image=1 - A bunch of artwork
http://i218.photobucket.com/albums/cc35 ... o1_500.jpg - Ubi's 25th Anniversary artwork
http://tinypic.com/view.php?pic=35alq2f&s=5 - Some cancelled Rayman title?
http://tinypic.com/view.php?pic=rupf9s&s=5#.UzHL-qh_uSo - Some cancelled Rayman title?
http://tinypic.com/view.php?pic=ctjiq&s=5#.UzHL9qh_uSo - Some cancelled Rayman title?
http://s019.radikal.ru/i615/1204/53/43c66989e31a.jpg - Not entirely sure
http://3.bp.blogspot.com/_qP0vOW6MdCc/S ... _tower.jpg - Pheonix Rayman 4 Artwork
http://raymanpc.com/forum/download/file ... &mode=view - Rayman Stickers
http://raymanpc.com/forum/download/file ... &mode=view - Hire Art
http://imagizer.imageshack.us/a/img833/1543/t02n.png - Rayman and Ed
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http://raymanpc.com/forum/viewtopic.php ... 00#p766581
Not a rare image, but some data on Pre-Rayman M.