We need a place where we can put excerpts and readings from the upcoming book. This is not exhaustive... Not yet anyway.   This is every revealed bit I have been able to find. If you know of any others, please post below!  Kaladin Chapter (Returning Home)
Source: http://www.tor.com/2014/09/30/brandon-sanderson-stormlight-archive-book-3-first-chapter/
Video/Audio: none?   Kaladin (and Tarah) Video: https://www.youtube.com/watch?v=GlDHUCemF9U&ab_channel=MichaelMiller   Dalinar Flashback #1 (Battle)
Source: http://www.tor.com/2015/10/23/brandon-sanderson-reveals-a-dalinar-chapter-from-stormlight-archive-book-3/
Video: https://www.youtube.com/watch?v=uNJiQROElck   Dalinar Flashback #2 (Dinner Party)
Video #1: https://www.youtube.com/watch?v=CMFx9hFkDzs
Video #2: https://www.youtube.com/watch?v=l4o-dWiwgqI
Transcript: https://docs.google.com/document/d/1TgW20NgNsPnMe1nxCxMu7jib2Bf9dZGMjaYgZJfKnM8/edit   Note: Two more Dalinar flashbacks in "The Thrill" for those who have purchased "Unfettered 2" http://www.17thshard.com/news/brandon-news/dalinar-flashbacks-in-unfettered-ii-and-stormlight-fan-film-r309/   Prologue: Eshonai
Audio (older, early draft): http://www.17thshard.com/forum/applications/core/interface/file/attachment.php?id=14217
Video (newer revision, but incomplete): https://www.youtube.com/watch?v=TNHscNkg2Ws
Transcript (based on older audio): http://www.17thshard.com/forum/topic/57932-oathbringer-prologue-spoilers/?do=findComment&comment=533740
      Eshonai #1.5 (attached to the end of the previous reading) https://www.reddit.com/r/Stormlight_Archive/comments/5saeg6/oathbringer_prologue_read_by_brandon_at_signing/dde6khz/           Eshonai #2 (Chasm)   Source: no source to reference. Read at your own risk.    Jasnah - this scene is legitimate, but may not be included in Oathbringer.  Source: http://www.tor.com/2014/08/06/stormlight-archive-scene-after-words-of-radiance/   Interlude #1: Ardent Alista
Source: http://www.17thshard.com/forum/topic/56954-2017-02-17-boskone-54-boston-ma/#comment-511614
Audio: https://drive.google.com/file/d/0B9fo0ba8ynPxLWpJYjQxVlZVRFk/view
Transcript: http://www.17thshard.com/forum/topic/56954-2017-02-17-boskone-54-boston-ma/?page=4#comment-538486   Interlude #2: Soulcaster Kaza
Source: http://www.17thshard.com/forum/topic/58578-ad-astra/?page=4#comment-561711
Audio: https://soundcloud.com/user-254460900/ad-astra-reading-and-qa
Transcript: http://www.17thshard.com/forum/topic/58578-ad-astra/?page=5#comment-563497   Adolin Flashback (Ryshadium)
This is an unverified third-hand account courtesy of @She Who Cannot Be Named , with additional concerns voiced by @maxal   Other Stuff:
Brandon's last update on Reddit: https://www.reddit.com/r/Stormlight_Archive/comments/5zidxz/oathbringer_spoilers_stormlight_three_update_7/
Brandon's Latest update on Reddit: http://www.tor.com/2017/03/16/revealing-the-cover-to-oathbringer-the-third-book-in-brandon-sandersons-stormlight-archive/
Cover reveal: http://www.tor.com/2017/03/16/revealing-the-cover-to-oathbringer-the-third-book-in-brandon-sandersons-stormlight-archive/
Amazon Blurb:     If there is anything else, please post here and let us know!