Here's a few things apparently out of the Grand History of the Realms book. the poster just kind of hand picked things relating heavily to deity changes or Myth Drannor:
1375 Year of the Risen Elfkin - Vhaeraun is slain by Eilistraee. Selvetarm is slain by a Darksong Knight of Eilistraee. The church of Vhaeraun is absorbed by the church of Eilistraee and the church of Selvetarm is absorbed by the church of Lolth.
1376 Year if the Bent Blade - Zhentarim withdraws from MD due to their drow allies falling apart due to Vhaeraun's fall. Black Network is given permission by the elves to openly use Moonsea Ride and Rauthauvyr's Road.
1377 Year of the Haunting - Srinshee returns to MD and offers Ilsevele Miritar the Ruler's Blade, Ilsevele then becomes the coronal.
Kiaransalee is slain by Q'arlynd Melarn.
1379 Year of the Lost Keep - Lolth attempts to destroy Ghaunadaur but he proves to be stronger and more ancient than she expected and flees the Demonweb Pits for Deep Caverns.
1380 Year of the Blazing Hand - High Mage Araevin Teshurr completes restoration of Myth Drannor's Mythal.
1383 Year of the Vindicated Warrior - Moradin leads assembled hosts of Dwarfhome on a crusade against Hammergrim. Gorm Gulthyn and Haela Brightaxe perish. Moradin slays Laduger and Clangeddin slays Deep Duerra. Hammergrim is destroyed.
1384 Year of the Three Streams Blooded - Siamorphe and Tyr quarrel over mortal affairs. Siamorphe leaves the House of Triad for Brightwater Sune's domain. Sune suggests marriage between Tyr and Tymora to set the celestial planes back in balance. Helm chaperones the courtship of Tyr and Tymora. Strange misunderstandings lead to the accusation that Helm's stolen Tymora's heart. Tyr is forced to challenge Helm to combat, before either are able to return to their senses Helm is destroyed. Heartbroken Tymora follows Tyr back to the House of the Triad. Although they have no proof the gods believe Cyric had his hand in all of this.
1385 The Year of the Blue Fire - Cyric aided and abetted by Shar murders Mystra in Dweomerheart. The plane disintegrates killing Savras and sending Azuth and Velsharoon hurling deep into the endless Astral Plane. Without Mystra to govern the Weave magic goes wild and destructive. This event is known as the Spellplague. Thousands upon thousands of mages throughout Faerun are either driven insane or killed by the effects of this. Many planes are shifted or destroyed.
Tyr, Lathander, and Sune confront Cyric and imprison him in his Supreme Throne placing him under house arrest for 1000 years.
Sages in centuries to come mark this as the end of the old world and the terrifying beginning of the new.
And here's the Shar related info:
A few of the hundreds of notes on what the future of Faerun holds in the last few pages of the Realms history compilation Grand History of the Realms.
Eleasias 20 - Shadovar agents recover The Leaves of One Night, a Sharran text that could be used to summon the Shadowstorm, an apocalyptic event that could raise Shar above the other gods.
Through the work of the Shadovar and Church of Shar, the entirety of the Anauroch desert becomes a dead magic zone for the Weave, allowing only Shadow Weave spells and magical items to function within its boundaries. Plans were made for this to happen to all of Faerun but they were distrupted by adventurers.
Sunlord Daelegoth Orndeir of Lathander is excommunicated and later begins recreating the Church of Amaunator after using epic magic to create a second sun over the city of Eversult that never sets.
Elient 13 - Adventurers who revealed a false temple to Mystra return with some kidnapped spellcasters. In their posession that have an unfinished letter purportedly discovered in the Plane of Shadow. This letter alludes to the Book of the Black, a secret of the Sharrans, and includes a scrap of paper with an alternative roll of years known to Sharrans as the Black Chronology. The significance of this discovery goes largely unnoted even as the Sharrans muster their resources to fulfill the events prophesized in the Book of the Black.
Uktar 2 - From three hundred fathoms beneath the Sea of Fallen Stars, the lost Netherese enclave of Sakkors is raised by the Shades to once again fly free over Faerun. The Empire of Netheril is reborn.
Uktar 11 - In response to the growing threat of civil war throughout Sembia, Selgaunt forms a military alliance and trade pact with the Netherese.
Uktar 11 - An immense kraken under the control of a Prince of Shade attacks the harbor and dock ward of Yhaunn in Sembia.
Uktar 29 - Saerloon's army, using teleportation circles, materializes outside Selgaunt.
Uktar 30 - The Battle fof Selgaunt begins and ends. The Saerloonian forces, bolstered by the green dragon Vendemniharan and summoned elementals, breach Selgaunt's walls. However, Selgaunt's forces repel the Saerloonians with the aid of two Princes of Shade--Rivalen and Brennus--and the timely appearance of the newly raised, floating Shadovar city of Sakkors. All elements of the Saerloonian army are destroyed of captured.
Feast of the Moon - Khelben 'Blackstaff Arunsun dies creating the Rhymanthiin, the City of Hope, in the High Moor.
Nightal 1 - Elyril Hraven, pristess of Shar, completes a ritual set forth in the empty spaces within the Leaves of One Night and summons the Shadowstorm. A planar rift is torn open over Ordulin in Sembia, and that portion of the Plane of Shadow known as the Adumbral Calyx pours forth. Ordulin is destroyed in the cataclysm, and the bulk of its denizens are killed. Volumvax the Divine One, also known as Kesson Rel the First Chosen of Mask, now a quasi-deity in service to Shar, emerges from the rift amid an army of shadows and shadow giants. Volumvax raises Ordulin's dead as shadows to bolster his own army.
Nightal 15 - Sharran assassins infiltrate the village of Shadowdale and attack Elminster's Tower. After a fierce battle, Elminster vanishes and his tower is blasted into ruin and hurled into the planes.
Several Zulkirs are killed in Thay from infighting.
Eleint 30 - Halaster Blackcloack and Undermountain are destoyed in a massive catstrophe as a great ritual planned by the Mad Mage goes wrong. Thousands of mages and adventurers receive strange visions.
Nightal 20 - Lolth and Elistraee do battle with the fate of the drow hanging in the balance. Selvetarm, Chamion of Lolth, is slain by a Darksong Knight in service to Elistraee using an artifact known as the Crescent Blade. Vhaerun attempts to assassinate Elistraee but is killed by his sister. The Church of Selvetarm is absorbed into the Church of Lolth and the Church of Vhaerun is absorbed into the Church of Elistraee.
Kiaransalee, drow godess of necomancy and undeath, fades from existence.
A Netherese spy is caught in Suzail and publicly hanged. This event touches off a short-lived conflaguration of hostilities with the Shadovars, which comes to be called the four Day War.
The last bit of resistance falls, and Mulhorrand's conquest of Unther is complete.
The restoration of Myth Drannor's mythal is complete.
Moradin leads the assembled deities of Dwarfhome on a crusade against the dark powers of Hammergrim. Gorm Gulthyn and Haela Brightaxe perish in the battle, but Moradin destroys Laduguer, and Clangeddin slays Deep Duerra. The Plane of Hammergrim disperses into the Astral to the sounds of the dwarf gods' victorious battle hyms.
The War of Gold and Gloom comes to an end when both the dwarves and the duergar are set upon by an illithid attack seeking to take advantage of the chaos. The mind flayers are repulsed and the surviving duergar are offered a place within the ranks of the dwarves.
To make a long story short, Tyr slays Helm due to a massive misunderstanding and intrigue amongst the dieties of the Triad. Though nothing can be proved, the gods sense the hands of Cyric in Helm's death. Ilmater leaves the domain of the Triad for Sune's halls.
This is the last year prophesized in Shar's Black Chronology, which stretches from 1352 to 1385 DR.
Unthinkable catastrophe unsues when Cyric, aided and abetted by Shar, murders Mystra in her home plane of Dweomerheart. The plane itself disintegrates at once, destroying Savras and sending Azuth and Velsharoon reeling into the endless Astral Plane. Without Mystra to govern the Weave, magic bursts its bonds all across Faerun and the surrounding planes and runs wild. In Faerun, this event is known as the Spellplague. Thousands of mages are driven insane or destroyed, and the very substance of the world becomes mutable beneath veils of azure fire that dance across the skies by ngiht or by day.
Many planes are shifted or destroyed as well. Only greater deities prove strong enough to maintain their realm against the resultant chaos. Tyr, Lathander, and Sune move against Cyric and successfully imprison the Black Hand in his Supreme Throne, under a sentence of house arrest to last one thousand years.
Sages in century to come mark the Weave's destruction in the Year of Blue Fire (the Year of the Revelation according to the Black Chronology) as the end of the old world, and the terrible beginning of the new.