I find that I'm always interested in using certain things, but never remember. Mostly, over time, I've developed a playstyle and it's hard to break out of what I'm doing, especially because it works.
Holy water, as an example. I always *want* to use it, but by the time I remember, the undead in question are defeated.
Consumables I never seem to use, off the top of my head:
1. Holy water
2. Arsonist's oil
3. Oil of diminution
4. Wizardsbane oil
5. Remedial potion
There are probably more, but these are the ones I can think of right now.
*
I'm not including ones that I don't use on purpose, like strength elixirs and such.
