Let's start with the latest batches of rumors. The first set is a few days old though.
Set 1
TaJaDoru will debut during the middle of the series, it requires a special Hawk medal.
The wings on the head get bigger and the eyes turn red.
Birth is able to use various capsules. With the capsules he can get, Shovel Arm, Crane Arm, Drill Arm and something called OOO Canon.
Kiyoto Maki is the one who developed the second Rider system as well as the Candroids. He's rumored to be played by Yuu Kamio. When this was first posted, the actor wasn't confirmed yet. It's now confirmed to be true.
Giru (The rumored name of the dinosaur Greeed, the name was first posted in August.) and TaJaDoru will be in the movie first.
SaGoZo's special ability is related to gravity.
The wings on the head get bigger and the eyes turn red.
Birth is able to use various capsules. With the capsules he can get, Shovel Arm, Crane Arm, Drill Arm and something called OOO Canon.
Kiyoto Maki is the one who developed the second Rider system as well as the Candroids. He's rumored to be played by Yuu Kamio. When this was first posted, the actor wasn't confirmed yet. It's now confirmed to be true.
Giru (The rumored name of the dinosaur Greeed, the name was first posted in August.) and TaJaDoru will be in the movie first.
SaGoZo's special ability is related to gravity.
Set 2
SaGoZo will debut by the end of the year.
Gamel gains his complete body, however he doesn't have all his medals and his powers aren't complete.
Mezool absorbs Gamel.
Someone called Akira Date will be the first one to use the Birth system, it's later passed on to Goto.
Gamel gains his complete body, however he doesn't have all his medals and his powers aren't complete.
Mezool absorbs Gamel.
Someone called Akira Date will be the first one to use the Birth system, it's later passed on to Goto.
There's a chance of a Kamen Rider W V Cinema film being made.
It's rumored to be a 2 part story about Accel and Eternal.
It's rumored to be a 2 part story about Accel and Eternal.
This is for the upcoming movie.
At the end of OOO's part, a Greeed-like warrior monster (Nobunaga?) searching for Core Medals heads towards Futo.
Core will fight TaJaDoru and CJGX.
The Skull to the left is actually the first time he transforms into Skull. The first time he transformed, he activated it's full powers. This created a crystal like head. He's actually called Crystal Skull at this point. 
The two monsters above are the two first Dopants, Spider and Bat, that Skull fights against. They are based on the two first monsters Kamen Rider 1 fought against.
Kogami Foundation's research facility finds the mummy of Oda Nobunaga and creates a homunculus out of it. A jelly like substance appears and disappears leaving many Cell Medals behind.
That thing in the box is the homunculus in the making.
The monster to the left is Armored Warrior Monster which is the main villain in OOO's part of the movie. This is only his incomplete body. However, if you look carefully you can see crab, lobster and scorpion features in him. By using the trick to enable sounds in the O Driver you can hear all those three animal names with a light blue color. The light blue colors are those who aren't grouped with OOO's combos. They are also thought to be the second Rider's source of power. When the homunculus was created, it left behind Cell Medals. It might be possible that they are connected to the second Rider.
