Still.. Just don't claim them as your own.
As you used a brush set which was free to use,
I don't think there is any problems rights wise,
but it can still be called plagiarism if you claim
them as your own.
On that note, you cannot market items made through
the same process as these, fyi.
Last edited by ThePirateKing; Sep 28, 2014 at 08:19 PM.