Hey @Gym Kirk! Welcome to the Marvel course!! The Pentel line of brush pens are a popular refillable option! Check out the Pentel Pocket Brush Pen (shiny black plastic,) it's a great all around ink brush with replaceable cartridges. You can also buy your own ink and refill the cartridges if you want. It's a great one to get started with. I also really like the fine point Pentel Brush pen (XFP5F) for rendering and most fine detail work, it's approximately the size of a #2 ink brush, and for more dry brush effects grab a Medium Point Pentel Brush Pen (XFP5M). Any of these options should cover most of your needs! Hope this helps!