With Drobita being changed to stack, I can think of a few other items that might be nice to stack, especially for certain RP purposes.
There's a Suturing Needle and Thread that casts CMW in Port Lucine's Academy/College that weighs 0.3 and doesn't stack, and really could.
I don't think it would hurt anything if Bruno's Curse Powder, Bergamots Powder, or Powders of the Hero's Heart stacked as well.
Especially the Bruno's Curse Powder, which the Kobolds in a certain area drop en masse and will eat your entire inventory with.
Thankee for reading!