Since I have just got my GIMP let's start with ...GIMP Brushes.
Number 1: http://fav.me/d20k1hj By ~MyLastBlkRose (https://www.deviantart.com/mylastblkrose) I have also Faved the ones I've downloaded from this wonderful person.
Number 2: http://fav.me/d11tp7j By :IconProject-GimpBC: Amazing Stocks. I will fav and download more from your gallery.
Number 3: http://fav.me/d2oizku By :IconLJFHutch: This blew me away. Amazing.
Now for the Photoshop Brushes. I myself don't use Photoshop but you lot that do will love these wonderful brushes.
Number 1: http://fav.me/d147zgr By :Iconredheadstock: I myself now want Photoshop but cannot affor