I came across this tool called Filter Forge. With it, you can change all kinds of parameters like colors, brightness and size but also how the texture looks. Take a look at these screens:
This is one of the original textures that comes with the application.
Now, by checking the Row Shift checkbox, you get this:
Row Shift off, 40 Chaos:
Tiles are now placed more randomly.
Tiles too big for your taste? Make em bigger!
Repositioning colors:
Different colors:
Some more tweaks:
Alien-ish texture:
Note that those smaller images on the bottom left are all different variation of the base (default) texture, so there's a lot you can modify.
You can also mess with lighting but that's not what i did with these.
Filter Forge isn't free, but there's a 30 day trial available on the Filter Forge website:
http://www.filterforge.com/Filter Forge is also available as a PhotoShop and Paint Shop Pro plugin.
You can also create your own filters for your own textures by using the filter editor:
(Rimrook can do it, he has tons of texers anyway :D)
Here's a list of key features:
? Filter editor
? Online filter library (browse and download over 6000 free filters!)
? Seamless tiling
? Bump and Normal maps
? HDRI Lighting
? 16- and 32-Bit Image Modes
? Floating-Point File Formats
? Smart Anti-Aliasing
? Dual-Core CPU Support
? Huge Resolutions (Max 65536*65536 pixels ? and it worked!)
? Standalone Version
? Adaptive Previews
? Presets
? Randomizer
? Favorites
So, if you're lazy and don't want to spend hours photoshopping, try out Filter Forge to create the texture you want, or go online and browse over 6000 filters and see what you like and begin modifying it in Filter Forge.