Reddit mentions of General Pencil CO. GPBM2-BP Factis Pen Style Eraser Carded

Nice collection! I have a few more items for you to consider adding, should you be so inclined:

• Uni Kuru Toga Pipe Slide: Plastic variant of the same line but with a retractable tip. Although I prefer the feel of the Roulette (which you already have in silver), I carry the Pipe Slide in my shirt pocket every day because it won't poke holes like the Roulette does. For those unfamiliar with the Kuru Toga line of mechanical pencils, they automatically rotate the lead every time you press it to the paper, avoiding flat spots and keeping it sharp on all sides. Note that this occurs each time you press down, not as you keep pressing. Thus, drawing a line rotates one notch (because you only set the tip to paper once), whereas writing letters, dots, etc. rotates multiple notches as you continue to repeatedly press the tip to the paper for each character.
  
• General's mechanical eraser: finer tip than most mechanical erasers, and nice pen-style grip. Refills are also available but I've found they're often cheaper locally. (Amazon sells 3-pack refills for ~$4 but my local college art store sells them for half that.)
  
• Tombow Mono mechanical erasers: Extremely fine erasers for detail, more than even General's, for uses such as erasing small lines while drawing. You can order sets of both shapes (round and rectangular) or just one, and they're available in silver or black.