Cosmere timeline

Brandon Sanderson's Cosmere is planned to be a massive literary undertaking, with around 40 books planned by the time Sanderson is done. There are around 12 full books so far, a compilation book containing most of his short-stories and novellas, and a graphic-novel trilogy.
 * MistBorn Era 1 (3): The Final-Empire, The Well of Ascension, and The Hero of Ages
 * MistBorn Era 2/Wax and Wayne (3 so far/1 more): The Alloy of Law, Shadows of Self, The Bands of Mourning, and The Lost Metal (not published yet)
 * StormLight Archive: The Way of Kings, Words of Radiance, OathBringer, Rhythm of War, 6 more to come
 * Standalone books (Sanderson intends to publish sequels): Elantris and WarBreaker
 * Arcanum Unbounded: a compilation book of various short-stories and novellas
 * White-Sand graphic-novel trilogy

=Ancient history of the Cosmere= Events taking place over ten-thousand years before any of the Cosmere books that have been published so far.

Ashyn (ancient) [X]

 * Ashyn, like the rest of the Rosharan solar-system, was created by Adonalsium
 * Development of Ashyn's Investiture predates the Shattering of Adonalsium
 * Ashyn's original magic involved Spren and a form of Proto-SurgeBinding
 * Development of Investiture predates the Shattering on most Cosmere worlds

First of the Sun (ancient) [X]

 * Development of the First of the Sun's Investiture predates the Shattering of Adonalsium
 * Development of Investiture predates the Shattering on most Cosmere worlds

Roshar (ancient) [X]

 * The formation of the planet Roshar
 * Estimated to be twelve or thirteen millennia old at the time of the True Desolation
 * The Rosharan supercontinent is created by Adonalsium's own hand
 * Presumably a few centuries or 1000+ years before the Shattering
 * The Singers developed and existed on Roshar at this time
 * Development of Roshar's Investiture predates the Shattering of Adolnasium
 * HighStorms and Spren have existed on Roshar since this time-period
 * Development of Investiture predates the Shattering on most Cosmere worlds

Yolen

 * Book series: DragonSteel (yet to be published)
 * The Shattering of Adonalsium
 * Adonalsium is Splintered into sixteen Shards: Odium, Honor, Ruin, Preservation, Ambition, Devotion, Dominion, Cultivation, Autonomy, Endowment, Invention, Whimsy, Valor, Mercy, a survival-related Shard, and a sixteenth unknown Shard
 * The first sixteen Shard-Vessels Ascend after being Invested with a Shard of Adonalsium
 * Rayse/Odium, Tanavast/Honor, Ati/Ruin, Leras/Preservation, Uli Da/Ambition, Aona/Devotion, Skai/Dominion, Koravellium Avast/Cultivation, Bavadin/Autonomy, and Edgli/Endowment
 * Identities currently unknown: Invention/Mercy/Valor/Whimsy/survival Shard/unknown Shard
 * All Investiture is divided between the newly-split Shards and preexisting magic-systems are fundamentally altered

=Classical history of the Cosmere= Events taking place long after the Shattering of Adolnasium but over a millennium before any of the Cosmere books that have been published so far.

Ashyn (classical) [X]

 * Humans settle on Ashyn at some point after the Shattering
 * Odium establishes a presence on Ashyn after settling on Braize and before the planet's devastation
 * Ashyn is devastated by the power of SurgeBinding and the DawnShards
 * Most of humankind on the world migrates to Roshar
 * Some humans remained on what was left of the planet's habitable parts
 * Odium follows humankind and first establishes a presence on Roshar
 * The Investiture on Ashyn shifts from its' original Proto-SurgeBinding and Spren form to its' present bacteria/virus-based magic-system after most of humankind has evacuated from the planet

Braize (classical)

 * Coming of Odium to Braize
 * Braize becomes the ShardWorld of Odium
 * Honor, with the help of Cultivation, binds Odium to Braize
 * Odium becomes unable to escape the worlds of the Rosharan solar-system
 * This is before Odium was able to Splinter Honor

Roshar (classical)

 * Coming of Honor and Cultivation to Roshar
 * Roshar becomes the ShardWorld of Honor and Cultivation
 * Coming of humanity to Roshar
 * Happens after Ashyn is devastated by SurgeBinders
 * Odium first establishes a presence on Roshar

Scadrial (classical) [X]

 * Preservation and Ruin come to what is now known as the Scadrian solar-system
 * Preservation and Ruin use their combined power to create the planet Scadrial
 * Scadrial becomes the ShardWorld of Preservation and Ruin
 * Post-Shattering time-period unknown: presumably several millennia before the Final-Empire
 * Creation of Scadrian humans by the cooperation of Preservation and Ruin
 * Knowledge of the Metallic-Arts was varied during this time-period
 * Allomancy was almost entirely unhead of until Rashek discovered the Lerasium beads
 * Feruchemy was the most widespread but was only found among the Terris
 * Hemalurgy was entirely unknown until Ruin revealed its' secrets to Rashek
 * Technology was more advanced with steam-power, clockwork, and the development of locomotion
 * Rashek murders Alendi after discovering the Well of Ascension and gains Preservation's power
 * Rashek alters Scadrial's orbit in an attempt to banish the Deepness, damaging the planet
 * Rashek transformed Scadrial into the World of Ash, creating the AshMounts and hardier plantlife
 * Rashek transforms non-Terris Scadrian humans into three forms: Nobles, Skaa, and Southerners
 * Rashek transformed Terris Feruchemists into MistWraiths so they could not oppose him
 * Rashek learns how to create Hemalurgic constructs: Kandra, Koloss, and Steel-Inquisitors
 * Ascension of Rashek the Lord-Ruler and the rise of the Final-Empire
 * Lasted a little over one-thousand years
 * Presumably happened several millennia after the creation of Scadrial
 * Ended after the death of the Lord-Ruler (see: Recent history of Scadrial)

Sel (classical)

 * Coming of Devotion and Dominion to Sel
 * Sel becomes the ShardWorld of Devotion and Dominion
 * Splintering of Devotion and Dominion at the hands of Odium
 * Happened before the Splintering of Ambition

Taldain (classical) [X]

 * Taldain was moved to what is now known as the Taldain solar-system
 * Unknown if it was Autonomy who relocated Taldain
 * Unknown if humanity came to Taldain before or after relocation
 * Coming of Autonomy to Taldain
 * Taldain becomes the ShardWorld of Autonomy
 * Unknown if this occured before or after Taldain was relocated
 * Unknown if this occurred before or after humanity settled on the planet
 * Coming of humanity to Taldain
 * Unknown if this occurred before or after Taldain was relocated
 * Unknown if this occurred before or after Autonomy settled on the planet

Threnody (classical)

 * Coming of Ambition to Threnody
 * Threnody becomes the ShardWorld of Ambition
 * Splintering of Ambition at the hands of Odium
 * Happened after the Splintering of Devotion and Dominion

=Recent history of the Cosmere= Events taking place within the last five-hundred years of the Cosmere books that have been published so far.

Ashyn (recent)

 * In the millennia after Ashyn's near-destruction, the world has become notable for its' floating cities

Nalthis (recent)

 * The ManyWar: a massive world-war on Nalthis
 * Happened some three-hundred years before the events of WarBreaker
 * Similar time-period: Final-Empire's closing years/first decades post-Catacendre on Scadrial

Scadrial (recent)

 * Book series: MistBorn Era 1
 * Collapse of the Final-Empire (Survivor's Gambit)
 * Catacandre (Final-Ascension)
 * Sazed becomes the Shard-Vessel of Harmony, uniting Ruin and Preservation
 * Harmony restores Scadrial to its' previous form
 * Scadrial is reborn as the ShardWorld of Harmony
 * Roughly 340 years before the events of Wax and Wayne
 * Similar time-period: The ManyWar of Nalthis

Sel (recent)

 * Book: Elantris

Taldain (recent)

 * Book series: White-Sand graphic-novels
 * According to Sanderson, it is the earliest series currently published in the Cosmere timeline

=Current events of the Cosmere= Events taking within about a decade of the latest published Cosmere books.

Nalthis (current)

 * Book: WarBreaker

Roshar (current)

 * Book series: StormLight Archive 1-5

Scadrial (current)

 * Book series: MistBorn Era 2/Wax and Wayne

=Near-future of the Cosmere= Events that will take place within the next century or so in Cosmere books that are soon to be published.

Roshar (near-future)

 * Book series: StormLight Archive 6-10
 * Will take place around a decade after the end of StormLight Archive 5

Scadrial (near-future) [X]

 * Book series: MistBorn Era 3 (set to be published from 2025-2027)
 * Probably set around a century after the end of MistBorn Era 3
 * Era 2 has a society similar to Post-Civil-War/Wild West America
 * Era 3 will be in the early computer age of technology with a 1980s type society

=Future Space-Age of the Cosmere= Events that will take place within the Space-Age of the Cosmere, at least many centuries down the line from the current Cosmere books, where futuristic space-travel is possible and the universe takes on a more sci-fi quality.

First of the Sun (Space-Age) [X]

 * Book series: Arcanum Unbounded (Sixth of the Dusk)
 * The planet has been visited by space-travelers within recent years, referred to at the Ones Above
 * Sixth of the Dusk and Vathi discover that the Ones Above wish to eventually rule First of the Sun and utilize the Investiture magics possessed by the Aviar birds of the planet
 * Sixth joins with Vathi's people to foil this plan and protect his world

Roshar (Space-Age) [X]

 * Roshar will either develop space-travel or be visited by space-travelers in this time-period
 * Food and items from Roshar have been taken across the Cosmere
 * Sixth of the Dusk has tried Herdazian food brought to his world

Scadrial (Space-Age) [X]

 * Book series: MistBorn Era 4 (likely to be published sometime after 2030)
 * Will take place an unknown amount of time after MistBorn Era 3
 * Near the end of the Cosmere timeline
 * Will feature advanced sci-fi-level Allomancy/Feruchemy-based technology