This is something I used to regularly struggle with as a musician and songwriter. Being consumed with originality I felt stress at the fact that, in a sense, all the possible songs have long been written. Every possible note combination whether vertically (harmony) or horizontally (melody) has been tried at least once. Generally speaking, Western music only has 12 notes to its variety and we've long discovered which ones work and which ones don't. It frustrated me to no end.

So, what do you do? You accept it for what it is and don't let that stop you. You build off the ideas that inspired you in the first place and you don't sweat the originality. You make songs anyways so that you practice the creative process over and over until eventually, you do find a sound or a style that you can call your own.

I think there's much to draw from that analogy. You'll get nowhere creating nothing, so you have to start creating something. Make something that is a clone of another product and find it's flaws or its weak points and make a product that fixes their issue or make your own without the flaws. Do this over and over and you will find your own unique advantage and audience for your product.

Also, keep in mind that in any business vertical, between having no business whatsoever and the few top selling ones are millions of businesses striving on just a piece of the market share. Even if a business idea already exists there may be a way to do it locally, or in another market, or leverage those ideas into another industry altogether.

Good luck and keep creating.