Object property “curing”: allows the item to be used like a unicorn horn to cure ailments.

Shopkeepers should pay you a small fee for killing a mimic that was generated in their shop. (Or at least give you the corpse for free).

Add a TDTTOE message about swinging your dead cat if you start hitting things with a wielded cat corpse. Also have a separate message “There isn’t enough room to swing your dead cat” if there are 4 or more walls adjacent to you.

Sanctuary in coaligned temples is granted only if your prayer timeout is nonzero.

Wielding a light source increases its radius by 1. Or possibly 1 if offhanded and 2 if directly wielded.

Allow a count for eating, or else have the character stop once they hit Satiated. (Note that numerous people have pointed out flaws with allowing the player to specify exactly how much they want to eat - for instance, it becomes trivial to stretch out a lizard corpse to every bite it provides).

You can convert spellbooks into scrolls. You may get scrolls related to the spellbook topic if possible, otherwise random. Possibly beatitude affects the number of scrolls produced.

Pets don’t go feral if you are both in Sokoban, even on different levels.