A lot of the folks here use patterns and textures from websites so I don't think that you'll have any problems until you start claiming something is yours without some sort of disclaimer like "original pattern by such n such and modified by whatshisname". If you're trying to make money off of that then I'd be inclined to say don't even try it cuz it might cause you some headaches (it all depends on how much modification is there and someone could argue that point for a long way). For our purposes here, it isn't really all that necessary to say where you got all of the patterns from...include that sort of info if you want. I use patterns all the time but they're all Photoshop default patterns and I use them in such small areas it's hard to notice them...so that means post em if ya got em. If you're going to make a map that extends from someone else's map then just say so and I think you'll be fine there, as well, so long as you don't try to sell the whole image with the other person's map. You could chop up your parts and sell those cuz the original map isn't on there. If people say "hey, that looks like so and so's style" then say thank you I tried really hard to get it to look that way.