Nice initiative. I hardly use any textures, but some may be very handy. Are they tiled, so you can repeat them? Otherwise I suggest you make them tileable. And I would make those photographs straight from above, without shadows, or they will look strange if you view them from another angle than how they're photographed.
Stitching is great; I used to make landscape images of 8 or so photo's all stitched together, and they hang on my wall now at 2m wide with every sandgrain visible.
They're tillable, shot in ambient twilight with camera light constantly on to create straight casting light, 1:1 ratio, grid, etc. Stitching is necessary because of limited resolution, megapixel quality. The previews are renders, not the texture. If I had a better camera with a wider FOV and better quality it wouldn't be necessary for a lot of what I'm texturing. Just can't wait to get out to the pass to take photos of rock forms.
IMO, texture implies it's a seamless, well, texture, otherwise it's just a stock photo, for some reason with depth map and bump and stuff hehe. At least when it's not bundled with a object for specific UV.
Reason I'm doing these is looking over RD's gallery with work using a lot of their products:
https://www.rd-textures.com/gallery/