Simple pencil clip I designed after trying many others. Works with hexagon and round pencils can also work with some pens and ever sharps.
Pencil will not slip out as it is retained to the notepad which also makes it less likely to stab you or break off.  The length is long enough to go past any retaining elastic the book may have but also thin enough to work with books that have retaining magnets.   Works best with “PLA Basic” but also works well with “AMS TPU” and “PLA Matte”.