I just create a complete timeline of DF-616 for Digimon Fusion Kai/Cross Generations. Like that YYGDM-01 timeline I created, I added references and future stories (but not too spoilish). Onto the history!
Disclaimer: Digimon/Dragonball Z/Kai/GT belongs to Toei Animation. Digimon Fusion Kai (not to confuse with the English title, Digimon Fusion, for Xros Wars) & YuYuGiDigiMoon belongs to Kanius. Digimon Accel Stream belongs to Chaosblazer.
-100,000 years ago: Huanglongmon laid out the foundations of the Four Digital Realms, which was originally a single realm. Before Huanglongmon, the Supreme Guardians and the Guardians were the watchers of pre-existing Digiworlds. This one Digital Realm became the watcher grounds for the Supreme Guardians. All of which were governed under the ENIAC and the Grand Supreme Guardian. Billsmon and Whismon are also created, that the former's role is to destroy planets as a role of balance, hence that he's called the Digi-God of Destruction. Whismon serves as Billsmon's martial arts master. Following a crisis with an ancient monster created by an evil sorcerer, all but one Supreme Guardian were killed/absorbed. Only one Supreme Guardian remains to this day.
-10,000 years ago: Somewhere in the nexus dimension, the CrimsonStardramon and its servants that parodied the Signer Dragons have fought the RedNovaDemon and digimon that parodied the Earthbound Immortals. The CrimsonStardramon's forces defeated RedNovaDemon's forces, but it come a price. The Signer Dragons became powerless and are scattered across other universes to an eternal slumber, while the CrimsonStardramon was sealed into four Crimson Digicores that are scattered across Huanglongmon's Central Realm in DF-616. Legends say that the user can grant any single wish from those digicores, and then the objects were scattered across the galaxy. If they are not return to the planet the wish was granted in 7 days, then the planet would detonate. Furthermore, the Crimson Digicores can corrupt anyone who has a black heart.
-5,000 years ago: After Huanglongmon's rise to prominence, the battle with the ancient monster forced the golden dragon to divide the single realm into four Digital Realms. All of them were designated according to the Four Paths of Chinese Mythology: North, South, East, and West. Huanglongmon created four Digimon and empowered them with authority to oversee their respective realms. You know which Sovereign watches over which realm.
-3,000 years ago: The war between the Beast and Human Digimon. Lucemon's rise and fall. Ancient Warriors sacrifice themselves and leave an essence of their powers through Spirits after destroying Lucemon.
-2,500 years ago: History of the Sephirots. The Ancients were temple priests for the Sephirot people back on the world where Skykos the Exodian Priest's power originated. Keter and Skykos battled for the supreme crown of who would rule Planet Sephirot. The battle lasted for hundreds of years, until the gem that the Ancients referred to as the Zero Unit, was forged to decide their battle. Ultimately, Keter and Skykos grabbed hold of the gem, granting them equal power. In the end, their powers became too great and destroyed Planet Sephirot. The remaining Sephirot who retreated took the Zero Unit with them, but Skykos' spirit pursued them. When they landed on Planet Void, the last of the Sephirot race evolved into descendants called the Galactic Pirates. They created Calumon as the catalyst to contain the Zero Unit, and as the key to unlocking the sealed powers of Digimon.
-2,000 years ago: Apocalymon first rips through the Wall of Fire and spill vast amounts of dark energy across the Digiverse. Various evil denizens including the Corrupts are born from this dark energy. Many dark realms are unsealed, releasing evil entities from the Dark Area and Dark Ocean. Mutalior and Burizalor are born. Burizalor is considered the cream amongst the crop of the Corrupts and receives the gift of leading the Corrupts against the Digital Knight Council.
-1,500 years ago: The war between the Corrupts and Digital Knight Council spills across the Digiverse.
-1,000 years ago: The First Ascendant, Alpha X, rises to power. He fought Pyronmon, an independent entity spawned from Apocalymon's power, and he was the first Zero user. Pyronmon was defeated, but he expelled his power in forcefully pass it to Alpha X. Overtime, the power of the Zero ability consumed Alpha X in becoming a monster and fought the Digital Knights. Alpha X eventually destroys himself along with his homeworld, Planet Primordial. Before he died, the Digital Knights retrieve his DNA to study this Ascendant power. The five Original Chosen were selected by Ebonwumon. Gennai takes up duty to train the orphans, allowing them to utilize Digivices that grant them powers to combat Burizalor's forces. The First Great War commences leading to Burizalor and his followers to be sealed behind the Wall of Fire. Shortly thereafter, Taito Yagami and his group defeat Apocalymon using their Legendary Armors to seal Apocalymon behind the wall. Second Great War occurs after Burizalor, Apocalymon, and his Corrupt forces are released by Millenniummon. Their release and collapse of the Wall of Fire causes the Eastern Realm to become warped, throwing its chronology out of sync with Earth again (thus one Earth day equals one minute in Digiworld). Burizalor establishes the Buriza Empire, an encompassing galactic federation that conquers and trades planets. The Dark Masters, Nightmare Soldiers, Demon Corps, and Nightmare Special Squad become a part of his regime. Cyrus betrays Taito and his friends, revealing to be Burizalor's spy. Taito confronts Cyrus and Burizalor. Burizalor destroys the central Digital World in the Northern Digigalaxy, destroying Taito and the last remnants of the Digital Knight Council. Gennai flees with the Digi Eggs and Digivices, later planning for the arrival of the new Digi-Destined. Manhunt ordered to find Gennai. Tags and Crests are taken by Burizalor, who promptly gives the Tags to Devimon. Cyrus/Shadramon scatters Crests across the Continent of Server. Burizalor hands Crest of Light to Myotismon. Burizalor and his cohorts seal the Holy Beasts/Sovereigns' powers, forcing them to retreat and turn into Digicores. These Digicores are sent directly toward Planet Spira, which are found by the Great Elder and guards them along with his people.
-500 years ago: Digimon Adventure (ep 1-39).
-1940s AD: Captain American: The First Avenger. Schindler's List.
-1975-1976 AD: Taito Yagami and company are born.
-Late 1980s AD: Taichi and the Odaiba children are born.
-June 1993 AD: Jurassic Park.
-March 1995 AD: The Odaiba digidestined witness the battle of Greymon and Parrotmon.
-May 1997 AD: The Lost World: Jurassic Park.
The Ascendant Era</u>
-August 3rd, 1999 AD (Digital/Real World Times Unsynchronized): Daimaomon's Conquest for Power and Digimon Fusion Kai (Ch. 1-54).
-August 6th, 1999 AD: The severely injured Burizalor is rescued by LadyMyotismon and converts himself to a cyborg.
-December 31st, 1999 AD: Iron Man 3 Flashback.
-March 25th, 2000 AD: Mutalior's Vengeance.
-Between 2000 and 2004 AD: The events of Digimon Zero Two with deviations.
-July 2001 AD: Jurassic Park III.
-2003 to 2004 AD: The Social Network.
-January 18th, 2004 AD: Digimon Fusion Kai (Ch. 55-58).
-June 20th, 2004 AD: Digimon Fusion Kai (Ch. 58).
-December 17th, 2004 AD: Digimon Fusion Kai (Ch. 58-71).
-December 18th, 2004 AD: Digimon Fusion Kai (Ch. 71).
-December 20th, 2004 AD: Digimon Fusion Kai (Ch. 71-72).
-December 21st, 2004 AD: Digimon Fusion Kai (Ch. 72-83).
-December 22nd, 2004 AD: Digimon Fusion Kai (Ch. 83-84).
-December 23rd, 2004 AD: Digimon Fusion Kai (Ch. 85-86).
-Between DFKai chapter 86-87: Yagami the Legendary Ascendant.
-December 31st, 2004 AD: The War Games (Digimon Fusion Kai Ch. 87-97)
-January 1st, 2005 AD: Digimon Fusion Kai (Ch. 97).
-January 25th, 2005 AD: Digimon Fusion Kai (Ch. 98).
-January 2005 AD: Digimon Fusion Kai (Ch. 99-102).
-February 7th, 2005 AD: Digimon Fusion Kai (Ch. 102).
The Triad Era</u>
-February 9th, 2005 AD: Digimon Fusion Kai (Ch. 103).
-February 12th, 2005 AD: Digimon Fusion Kai (Ch. 104).
-February 15th, 2005 AD: Digimon Fusion Kai (Ch. 104).
-February 23rd, 2005 AD: Digimon Fusion Kai (Ch. 105).
-February 24th, 2005 AD: Digimon Fusion Kai (Ch. 105).
-February 25th, 2005 AD: Digimon Fusion Kai (Ch. 106).
-June 2005 AD: Batman Begins.
-Between July 2005 and 2006 AD: Batman: Gotham Knight.
-November 4th, 2005 AD: Across Dimensions.
-November 26th, 2005 AD: Digimon Fusion Kai (Ch. 107).
-November 27th, 2005 AD: Digimon Fusion Kai (Ch. 108-109).
-March 26th, 2006 AD: Digimon Fusion Kai (Ch. 110-115).
-March 29th, 2006 AD: Digimon Fusion Kai (Ch. 115 where X explains about the Ascendant Legacy).
-July 2006 AD: The Dark Knight.
-August 2006 AD: Siege of GranDracmon.
-November 4, 2008 AD: Barack Obama is elected president.
-Between 2006 and 2009 AD: Lucemon's Revival. Yagami Second Coming. Digimon Accel Stream Season 2.
-April 8th, 2009 AD: Digimon Fusion Kai (Ch. 115 Epilogue).
-May 2009 AD: Digimon Fusion Kai (Season 3).
-May (After the D-Reaper conflicts) to October 2009 AD: Iron Man.
-Between 2009 and 2010 AD: Digimon Data Squad. Battle of Gods.
-2010 AD: Iron Man 2. The Incredible Hulk. Inception. Kick-Ass.
-2011 AD of YYGDM-01: The Valkyries Advent.
The Cross Era</u>
-June 2011 AD: Cross Generations (Crimson Digicores Saga - Bebimon Saga)
-Between June 2011 and December 2011 AD: Digimon Next.
-July 22nd, 2011 AD: Captain America wakes up in Time Square and meets Nick Fury after suspended animation for 70 years.
-December 15th, 2011 AD of DF-616: Curtain Call Episode in Across Convention Theme Park.
-March 2012 AD: Project X.
-May 4th, 2012 AD: Cross Generations (Super Jax Saga). The Avengers with deviations takes place.
-May 5th, 2012 AD: Cross Generations (Shadow Dramon Saga/The Dark Ending).
-September 2012 AD: The Amazing Spider Man.
-December 2012 AD of YYGDM-01: The Wrath of the Defiants.
-December 24th - 25th, 2012 AD of DF-616: Iron Man 3.
That's all for the timeline. Updates will come as the story progresses.