I try to credit things I purchased in the Marketplace here, as a community courtesy and I try to write in the test a thanks for any freebie.  But in all honesty, there are times when I just can't find who made something.  Maybe if every second product creator didn't name their readme file "readme"...

If I bought it from Daz or elsewhere, then I figure the sale is courtesy enough.

I'll gladly tell anyone who drops me a note where I got something if I can find it.  I once went on a net search for some freebie photoshop brush I had used in post work .  I was just glad to help.