Several ideas, some of them I've been working on recently, some are always bugging me at the back of my head.
1. Early industrial revolution, a journalist photographer of wildlife is sent to a recently and secretly discovered island, his job is to catalogue new species, but he was never expecting The dangers he'd find...
-photography gameplay inspired by Pokemon Snap, with a touch of survival like Monster Hunter. An action game where killing beasts is not the objective but rather taking the best pictures (which only happen when you approach danger by several means like sneaking, etc).
-i thought about it when the WiiU came out. Thinking using the gamepad as a camera. Now it can be good for VR.
2. A platformer action game where you're a soldier sick of the government Military and decides yo take it out without using violence.
-short, fast paced levels. Where you have to memorize enemy patterns to duck, jump, slide evading bullets and projectiles.
-levels are like 5-30 sec long
3. I'm currently working on the story. But basically the idea in gameplay is that you control a kid that can barely carry a huge slab of a sword (Berserker like giant sword) u use the sword in awkward ways to defeat the enemies until you get strong. At the ending your character has progressed to the level that he can carry the giant sword with one hand and he's ultra strong (DBZ Brolly level or Sakura from Danganronpa level)
-dark fantasy setting
4. a secret (not so secret anymore) project where you wander the earth in search of 18 swords. You travel in your Motorbike. Solitary exploration game, in a Scotish like environment. I'm designing the story scenario, and character atm.
5. And a project we did at school to win a funding contest. But couldn't do it at the end, the professor said it would never sell.
Imagine an arcade racer using spaceships and equipping special weapons for each character. Kind of like FZero competitions but without racetracks, just flying in space towards a goal, the means you use to reach it are your own.
-Thor Ragnarok has a scene that protrays the feeling of the races.
-Visuals like FZero and Daft Punks animated movie.
And many more

More ideas come to mind all the time making impossible to develop all. I mostly get my ideas while sleeping and dreaming.
I certainly would love to lead a team to make these.
Another one would be to make the "Zelda killer" a OOT level game that redefines an era. But I'm not shiggy, nor work at Nintendo u_u