Entrepreneurs spend a great deal of time working on ideas and concepts before they even take pen to paper or fingers to keyboard to place the idea into a tangible form. These ideas can consume you, keep you up at night and take over your weekends and spare moments, pressing you onward until you act upon the idea to make it something real.
Most people so inclined to try and turn their ideas into reality might not immediately jump to the conclusion that their ideas aren't original. That's not to say that they have intentionally copied the ideas of others in an attempt to pass them off as their own; rather, that people have been innovating across the ages, and as more and more people gain access to knowledge and resources, the more likely it is that your idea has been stumbled upon elsewhere. But if you're not looking for it, you might never find that other idea or creation so close to your own.
When you're starting the creative process, you want to make sure that what you create is sufficiently original, and is something that you can turn into a concept or product to use. And that means that you have to avoid infringing upon the IP rights of others. As we often say, ignorance is no defense, so you can't charge headlong into your project merely hoping that everything will work out. As tedious as it may seem, sitting down and doing a search of patents, copyrights and trademarks as applicable is a necessary step of the creative process if you want to be successful.
The existence of other ideas or works in a similar space to your own shouldn't scare you off from trying to do your own thing. After all, you are someone with a unique perspective that can approach these ideas from a new perspective and bring a new tact to old ideas. And much of innovation is building off of the previous work of others to create entirely new things. But before you spend untold hours trying to create your new thing, it's vital to make sure it's not time wasted on an already existing idea.