Back in the days when I did digital scrapbooking working in Photoshop, I discovered a site, Shadowhouse Creations created by Jerry Jones. Jerry generously creates these textures and offers them for FREE to anyone who would like to download them.
Below are some samples using various Shadowhouse Creations textures and the Diana Photo app.
Here's the most recent set featured on his site - clicking on the image will take you to Shadowhouse Creations so you can download the zip file. Most of the files in this set are 3600 x 2800 pixels.
Below is an image I made using one of the textures from this set and the Union App ($1.99) to do the layering and masking.