Art Bits - Ep 04 - How to make a ballpoint pen brush in Photoshop - YouTube
3 Ink Brushes for Photoshop by pixelstains on DeviantArt
26 Marker Pen Brushes - Photoshop brushes
Kyle's New Technical Pens for Photoshop | These new technical pens will be included in my Ultimate Lettering brush set for #Photoshop, which you can preorder now at 25% off the regular