Hey guys so I had a lot of thinking and I can’t just find the perfect idea…
I m looking for something unique, nothing related to FPS games… I don’t want guns in the game or much violence… that is pretty common these days… audience wants new ideas, new games…
Something which would make sense to play in multiplayer, like co-op type or something.
Btw if u want to work with us… so you don’t fell like your idea got stolen when you see our game published and maybe with success xd, you got me.
There are countess threads about this all over the internet.
if they are countless then they aren’t unique … 
Then why do you need to ask here? Use imagination, play Indie games, casual games, get inspirated… Play mods of games, you know, that stuff. When you have played a lot, then inspire yourself in something you really liked and try to get it to a whole new level. That’s all I can say.
Unique is fairly hard to come by these days; you’d need technology to change drastically to truly create something unique and even then the only unique part would be the interaction. Try resurrecting an older idea or converting a non-digital game to digital.
Examples:
Marble Madness (Idea Resurrection) - I had it for the NES and enjoyed it.
House of Cards (Adaptation to digital, idea is my own) - You construct a house of cards. Design the game for a platform that has a gyroscope then you can have the structure fall down if the device isn’t held stably or if the player doesn’t correct for destruction events thrown at them by the game (earthquakes, wind, etc.). You could possibly combine this with a Sim City style and allow the player to build a city out of cards to then destroy. This could be an ideal game project for use with the Leap Motion controller.
The idea isn’t truly unique; like pulling ideas from Sim City. It’s attraction points are its pointlessness and destroying something after building it.
You could also look at concept artwork and see if that inspires you. I’ve made character back stories and rough game concepts using that method before (when I say rough, I mean the design document is 1 page or less and usually more plot/setting oriented).
Look through the WIP forum. I’m sure there are plenty of ideas in there.
Just simply do what valve does, take a look at mods of games and remake them, sell them and earn millions :D. In all seriousness though, I would make an fps simply because most people don’t want anything new. There are several templates around so they are easy to make, and will probably get more respect than any innovative idea you could come up with. If you do want to make something new though, I think Richard Ws’ post has some good tips.
The way I come up with interesting ideas is to try and warp something that exists in the real world, and mix it with something else. For example, I was working on a game about dreams, and needed a good puzzle element. When your in the second stage of sleep you begin to loose consciousness, and so I figured I could represent that by having the level go slightly wacky in some way. I then thought about something I could mix in with it to make it more defined, and so I thought about Déjà vu. I then realized I could mix the two together, and have parts of the level that repeat themselves, one copy being able to be changed while the other cant.
You can do that with almost everything, just try and be creative
Get out pencil and paper, doodle, and see what you come up with.
Unique can also be something simple,there are lots of ways to make the game original such as putting very interesting character models in the game or having a unique design for the game.
What you could do is to try to find a way to make your game style(textures and models) look very different from any other game.
But if you are looking for a co-op idea you could make a top down view game such as Pikmins Adventures or you could make a side-scrolling game where with friends you explore the levels as in Little Big Planet or Puppeteer.
You need to do some research into videogames so that you can come up with your own idea.By that i mean playing videogames and thinking about what would make that videogame funner.And trying to find information on videogames on the internet.