I'm addicted to discbound and I have purchased everything in your line. Thank you for making such awesome versatile sets. I use these for absolutely anything and everything. I would love more shapes, bigger shapes (yes bigger than A&) and maybe some long skinny grocery list type ones. I'm a chronic list maker! Anyhow, I have made mixed media art journals with these - using watercolor and stiff cardstock and they always cut beautifully. I cut a bunch of magazines up for glue journals and made them discbound so I could even do a study of my art style progression. The sky is the limit with these. I feel I'm a decent artist, so I've also made artcard sketches into discbound books to send to my artsy (but not don't like to sketch) friends in themes that they enjoyed for them to color later.
One critique I would have to say is that I often get my discs elsewhere because your smaller sized disks - while perfect for swatch books etc - are not great for mixed media thicker bigger discbound books. Its a little humble grumble, so take it with a grain of salt, because even though I rarely use your discs... the dies get used and abused to the point I'm contemplating 'spares' in case they ever retire. "