Here is EVERYTHING seen in the video:
(Note: the few things I remain uncertain about are Italicized in parentheses with a question mark at the end)
Cybertron Vector Prime surrounded by clockworks.
G1 Planet Cybertron in space, with flashes of the Kronosphere, the Time Window, the Teleport Gate, the wall of a Quintesson banishment chamber, and the Dragon Mound.
Several Prime Vehicons engaged in trench warfare.
G1 Springer, Armada Jolt, G1 Sandstorm, Energon Bulkhead, Cybertron Evac, and Cybertron Jolt in a grassy field.
Energon Mirage, G1 Scourge, Cybertron Thunderblast, RiD 2001 Sky-Byte, and the Armada Sea Mini-Con team observing a wrecked BWII Galvaburg II.
RID 2015 Aerobolt, Beastformers White Leo, BWII Lio Junior, and G1 Steeljaw in the ruins of a building.
Cybertron Thundercracker, Animated Blitzwing, G1 Swindle, BM Tankor, Armada Powerlinx Demolishor Victory Kakuryu and BWII Megastorm.
A warzone on Junkion, with Junkyard carrying Greasestain on his back while Ashtray readies his weapon. Another Junkion stands by in the background.
G1 Ratchet lies battered on his side in vehicle mode, while G1 Jazz lies next to him upside-down in vehicle mode.
G1 Metroplex, Masterforce Grand Maximus, the BWII Yukikaze, G1 Broadside (with G1 Fireflight and (two other jets?) resting on his carrier mode), G1 Air Raid, G1 Skydive, G1 Silverbolt, and G1 Fortress Maximus.
A fallen Decepticon Warrior from "War Dawn".
Several destroyed Warriors and Dropkicks from "War Dawn", lying on a shoreline walked by the Rescue Patrol Team (Holi, Boater, Fire, and Pipo) from Victory, and Cyberverse Croaton.
Victory Holi looks up.
Masterforce Hydra and Buster with their Transtectors.
G1 Starscream, G1 Ion Storm, G1 Acid Storm, G1 Nova Storm, the Thunder Arrow from Victory, Victory Hellbat, Victory Leozack, Victory Guyhawk, Animated Blitzwing, Animated Blackout, Animated Lugnut, (a Prime Insecticon?), (Go! Dragotron?), (another Prime Insecticon?), four Jet Vehicons from Prime, BWII Gigastorm, G1 Trypticon, Armada Tidal Wave, G1 Scorponok, and the Nemesis from Prime.
Starscream flies with Kremzeek inside his cockpit, flanked by BWII Starscream, (Victory Leozack?), Animated Waspinator, and Armada Starscream.
Masterforce Wilder and his Transtector stand over the murdered Pis in a rainy ruined city.
Good guys galore: BW Neo NAVI, BW Neo Big Convoy with a Matrix Cannon, G1 Rodimus Prime with the G1 Matrix, G1 Optimus Prime, Victory Star Saber and Jan, BW Optimus Primal, RID 2015 Bumblebee with a Decepticon Hunter, Prime Optimus Prime, Masterforce God Ginrai, BWII Lio Convoy, Go! Kenzan, Cyberverse Optimus Prime, Zone Dai Atlas with the Zodiac, G1 Moonbase One, G1 Moonbase Two,Animated Optimus Prime, EarthSpark Optimus Prime, the G1 Ark, Energon Grindor and Kicker, Armada Optimus Prime, G1 Fortress Maximus, RID 2001 Optimus Prime, and Cybertron Optimus Prime.
Bad guy bosses: BW Neo Magmatron, G1 Megatron, BW Megatron, Cybertron Megatron with the Planet Map, Victory Deathsaurus, RID 2015 Megatronus, The G1 Nemesis, BWII Galvatron, RID 2001 Megatron, Cyberverse Megatron, Go! Guren Dragotron, Masterforce Overlord, EarthSpark Megatron, Zone Violengiguar, Armada Megatron armed with all three Mini-Con weapons (the Star Saber, the Skyboom Shield, and the Requiem Blaster), G1 Scorponok, Animated Megatron with Isaac Sumdac, and Prime Megatron with the dead Prime's arms and the Dark Star Saber.
Cybertron Megatron and Nemesis Breaker combine into Dark Claw Mode to fight BWII Lio Convoy's legendary Green Warrior form armed with BW Neo Magmatron's Magma Blade.
G1 Fortress Maximus, Victory Star Saber, Masterforce God Ginrai, RID 2015 Optimus Prime Supreme Mode and Cybertron Optimus Prime all bear their respective swords.
Cyberverse Optimus Prime, RiD 2001 Optimus Prime Battle Mode, BW Neo Big Convoy, Armada Optimus Prime Super Mode, and Energon Optimus Supreme all fire their weapons.
Prime Miko chills with her guitar on Prime Bulkhead.
Prime Bulkhead, Prime Bumblebee, Prime Arcee, Armada Laserbeak, Armada Alexis, Prime Miko, Armada Grindor, Prime Raf, Armada High Wire, Armada Rad, Prime Jack, Armada Carlos, Armada Sureshock, Armada Fred, and Armada Billy.
The Illumina II from Victory (piloted by Jan and Illumina), and the Cobybot from Cybertron (piloted by Coby and Lori).
RiD 2001 T-AI holding BWII Artemis's hammer, Q-Transformers Bumblebee, BWII Moon, Q-Transformers Optimus Prime, BWII Artemis, and Q-Transformers Lockdown.
Masterforce Goshooter, Masterforce Minerva, Masterforce Cab, Energon Energon Ironhide, Energon Kicker w/ the Energon Saber, and Animated Sari Sumdac, with Ocean City from Energon in the background.
Roses held by Akira from Zone.
Aligned Optimus Prime: Three Bodies Evolution (Prime Optimus Prime with the Forge of Solus Prime, Go! Hunter Optimus Prime with the Star Saber, and Go! Optimus Exprime.
Go! Optimus Exprime, Go! Gekisoumaru, and Go! Kenzan combine into DaiGekisou.
Tobio and Isami stand on the chestplate of DaiKenzan, along with both their grandfathers, Kotarō Fūma, Ryōma Sakamoto, Bokuden Tsukahara, Musashi Miyamoto, Sasuke Sarutobi, and Musashibō Benkei all from Go!, all stood atop DaiKenzan's shoulders.
Cybertron Bud, Cybertron Safeguard, Cybertron Vector Prime holding the Planet Map.
G1 Optimus Prime traveling through "the other side of the Matrix" seen in the BW episode "Coming of the Fuzors (Part 2)". His colors shift between his normal colors, dead colors, and the Bump of Chicken Bass Convoy colors, as the following images flash before him: His death from TFTM, the death of Transmetal 2 Dinobot from the BW episode "Nemesis Part 2", the death of Prime Cliffjumper from the episode "Darkness Rising, Part 1", Armada Powerlinx Starscream's death (featuring the Zapmaster-colored Swindle) from the episode "Cramp", the death of Animated Prowl from "Endgame, Part II", and the death of God Ginrai (featuring Jan) from the Victory episode "Ginrai Dies!!"
G1 Optimus Prime and BW Transmetal Optimus Primal turn into sparks that merge together into BW Optimal Optimus, while G1 Megatron and BW Transmetal Megatron become orange sparks (like how Beast Megatron's spark was orange in Beast Machines) that merge into BW Transmetal 2 Megatron. As they fight, images of BM Megatron and Optimus Primal flash before them.
Masterforce Megajet (piloted by Lady Mega) and Gigatank (piloted by Lord Giga) combine into Overlord, who fires missiles at Animated Wingblade Optimus Prime armed with the Magnus Hammer.
G1 Dirk Manus and Marissa Faireborn about to share a kiss.
The G1 Matrix of Leadership.
Armada Sparkplug holding up the Armada Matrix, G1 Rodimus Prime holding up the opened G1 Matrix, and Zone Dai Atlas holding up the Zodiac.
Movie Optimus Prime, Movie Ratchet, Movie Ironhide, Movie Bumblebee, and Movie Jazz.
Movie Bonecrusher, Movie Megatron, Movie Barricade, Movie Brawl, Movie Starscream, and Movie Blackout.
Movie Optimus Prime and Movie Megatron fight in homage to Panty and Stocking.
ROTB Optimus Primal close up.
ROTB group shot: Wheeljack, Arcee, Rhinox, Airazor, Bumblebee, Optimus Primal, Mirage, Cheetor, and Stratosphere.
G1 Optimus Prime and Megatron continue fighting until they stand before RID 2015 Denny Clay, RID 2015 Russell Clay, G1 Daniel Witwitcky, G1 Spike Witwicky, G1 Carly Witwicky, EarthSpark Alex Malto, EarthSpark Robby Malto, EarthSpark Dot Malto, EarthSpark Mo Malto, RiD 2001 Kiko Onishi, RiD 2001 Koji Onishi, and RiD 2001 Dr. Onishi.
The G1 leaders in front of the four families are replaced by EarthSpark Megatron and Optimus Prime, who shake hands in peace.
G1 Unicron's severed head floats in space.
G1 Planet Cybertron vibrates in space, with G1 Unicron's severed head emerging from behind it as the credits roll.