The last but not least source to find inspiration is through..
People as in the person him/herself and people as in their works.
People and all of the history behind them always became a good inspiration. You can start with those who were known by plenty, such as Frida Kahlo, Salvador Dali, Napoleon Bonaparte, Hemingway, and many more. Explore their thinking and principles, their way of life, history and style, and try to see them from different points of view.
And then you may wanna try to get inspiration from ordinary people that you know around you. Everyone always has a story to tell, lovely things to be shared, style to be applied, and lesson to be learned. Absorb them and express them with your ways. It could even be inspiration sources for generations to come.
As in people's work, you can get some inspiration just by seeing other people's work that somehow evokes ideas in you. But be careful, don't fall into the trap of plagiarism.
Being inspired means taking the general ideas, and changed it or infused it with your own character and aesthetic values to create a completely different things. It should carry a part of you in it.
Well, those are how I find my inspirations. I hope it would help you and maybe you will find some other ways to get your inspiration bank full, and share it with me? :)
Ps: Frida Kahlo painting by Anna Davis