Legacy

A massive crossover between Godzilla, Gamera, My Little Pony: Friendship is Magic, Bionicle, Warcraft, The Last Unicorn, Legend of Korra, Transformers Prime and Princess Mononoke and a sequel to Godzilla vs. Destoroyah.

Prequel Series/ Countdown to Legacy
The fic has a series of prequels which lead up to its events, some are in canon with their respective source materials while others ignore their own continuity called Countdown to Legacy.

Transformers Prime: Set after the events of Episode 19 of its second season. It introduces the Dinobots, Ultra Magnus, Jazz, Springer, Kup, Hot Shot, Ironhide and Sideswipe for the Autobots while also bringing in Shockwave as well as introducing Sharpshot, Kickback, the Combaticons, the Constructicons, Lockdown, Lugnut, Blackout and Barricade for the Decepticons. A band of Autobot survivors, among them being the Dinobots and Ultra Magnus arrive on Earth after tracking an energy source on the planet, unaware they are also being followed by Shockwave and his own Decepticon team.
 * Arrivals:

My Little Pony: Friendship is Magic: The continuity is set after the events of Season 3 but has Nyx from PenStroke's fanfiction Past Sins. Celestia has a conversation with the Changeling Queen Chrysalis who reveals she may have a darker past with the Princess of the Sun.
 * Conversations in the Dark:

Legend of Korra: Set after Season 1. Korra and Mako go out on their first date unaware they are being eavesdropped by Bolin and Asami.
 * The Avatar's Date:

Gamera: Set in its own continuity. In this continuity, Gamera is the last of a terrapin race of creatures born from the Mana stream called Makulae while the Gyaos as well as their queen Irys are born from the Dark Mana Stream. A swarm of Gyaos, led by Irys, heads towards Okinawa while Gamera rushes in an attempt to intercept them in time.
 * Siege:

Bionicle: Set in the Mahri Arc but Matoro is still alive. The Toa Mahri have to deal with the Barraki while also holding off Makuta Teridax.
 * Battle in the Depths:

Princess Mononoke: Set a few months after the events of the first movie. Ashitaka and San meet again where they first encountered each other.
 * Where We Last Met:

Warcraft: Set in Cataclysm but Deathwing, Sintharia, Nefarian and Onyxia are still alive. The four remaining Dragon Aspects, Alexstrasza, Kalecgos, Nozdormu and Ysera attempt to defeat Deathwing in Grim Batol.
 * Battle of Grim Batol:

The Last Unicorn: Set three months after the events of the movie. Lir, Amalthea, Molly and Schmendrick meet again for the first time in months and recollect their experiences.
 * Second Meeting

Godzilla: Set 9 years after the events of Godzilla vs. Destoroyah. Godzilla Junior, after a battle with a biomechanical monster comes across a female of his kind as well as several other monsters. Meanwhile, four monsters come across the body of King Ghidorah.
 * Monster Island*:


 * Note: This leads directly into the events of Legacy.

Major Battles in Legacy
Battle 1:

Godzilla vs. Gamera

Combatants: Godzilla, Daihime and Gamera

Outcome: Draw

Battle 2:

Monster Island, Mane 6 and Toa Mahri vs. Gyaos and Changelings

Combatants: Godzilla, Daihime, Anguirus, Rodan, Kamacuras, Kumonga, Varan, Vagnosaurus, Gorosaurus, Baragon, Shiigan, Megaguirus, Gezora, Ganimes, Ebirah, Kamoebas, Manda, Barugaron, Jyarumu, Balkzardan, Twilight Sparkle, Rainbow Dash, Rarity, Fluttershy, Pinkie Pie,  Princess Celestia, Princess Luna, Princess Cadence, Nyx, Spike, Shining Armor, Jaller, Hahli, Nuparu, Matoro, Kongu, Hewkii, Gamera, Gyaos, Changelings

Outcome: Victory

Battle 3:

Mane 6, Team Prime, Godzilla, Daihime, Gamera, Team Avatar, San, Ashitaka, Moro, Amalthea, Lir, Molly, Schmendrick, Dragon Aspects and Toa Mahri vs. Black Dragonflight, Insecticons, Gyaos, Vehicons, Visorak and Shadow Dragons

Combatants: Godzilla, Daihime, Gamera, Korra, Naga, Mako, Tenzin, Asami, Lir, Molly, Amalthea, Ashitaka, San, Moro, Alexstrasza, Ysera, Kalecgos, Nozdormu, Twilight Sparkle, Rainbow Dash, Applejack, Rarity, Pinkie Pie, Fluttershy, Princess Celestia, Princess Luna, Princess Cadence, Shining Armor, Spike, Nyx, Optimus Prime, Jazz, Arcee, Bumblebee, Grimlock, Sludge, Swoop, Snarl, Slug, Ironhide, Ultra Magnus, Sideswipe, Hot Shot, Ratchet, Springer, Gyaos, Vehicons, Shadow Dragons, Insecticons, Black Dragonflight, Deathwing, Visorak, Nefarian, Sintharia and Onyxia

Outcome: Unknown (Schmendrick accidentally teleports himself, San, Ashitaka, Godzilla, Moro, Amalthea, Lir, Molly, Korra, Mako, Asami, Bolin, Pinkie Pie, Twilight Sparkle, Rainbow Dash, Rarity, Optimus Prime, Grimlock, Spike, Nyx, Kalecgos, Alexstrazsa, Ysera, Nozdormu, Jaller, Hahli, Kongu, Matoro, Nuparu and Hewkii  out of the battle)