This collection of awesome psychadelic stained paper textures are from the Lost and Taken site, a great resource for high quality textures. If you are interested in downloading all of the images in a pack, the link to the download page is at the bottom of the article.
There are 12 stained paper textures below that I created by mixing together some dark wood stain and water, then dipping cardstock into the mixture. The paper was stained with some really neat patterns and visuals. I then added some bright colors to the textures in photoshop to give the end result.
Click Here to go to the download page.