Using genocide breaks pacifist conduct.

You can dip fruit into an uncursed potion of water to squeeze its juice out and turn it into a (maybe diluted) potion of fruit juice. However, this could be abused if fruit juice is smoky.

Antimagic lamps, which cast an magic-denying field in their light radius. Your magic doesn’t work, but neither does anyone else’s, with everything behaving as if cancelled.

When you are carrying a candy bar, ants are attracted to you, even if peaceful. Candy bars should also be a treat for pet ants.

Potion of coffee, a nonmagical potion which confers temporary sleep resistance and, while the sleep resistance is still active, a small bonus towards the odds of learning a spell from a book successfully.

If a monster kills your pet and then you personally kill that monster, you get a message about avenging the pet’s death.

When zapping a wand when confused, one of the potential random directions to zap is at yourself. This could potentially apply to any directional prompt, not just wands.

A tree hit by a fire ray or explosion should instantly incinerate, provided it’s not marked non-diggable (petrified). Likewise, a tree hit by a disintegration blast should disintegrate.

Alignment penalty, or possibly even angering your god, for Monks and Priests for consorting with a foocubus.

The ability to chat with intelligent pets and give them basic strategy directives, such as what type of attack they should be favoring, or whether they should stop attacking and stay by your side. Opinions vary as to whether this should be limited to intelligent pets or not.