A bag of traps, a chargeable magic tool which creates a random trap on your space. Alternatively, have it be a wand of trap creation, which would be nondirectional.

There could be some way to force creation of a specific trap, perhaps by wielding a component which gets consumed, such as arrows for an arrow trap, or a potion of water for a rust trap.

It should be possible to trigger some types of traps by throwing or shooting an object onto them. This does open up the possibility of chain reactions, such as triggering a land mine and objects flying around and landing on other traps, so care should be taken when implementing it.

Whether each trap type should be triggerable by object requires deciding what the triggering mechanism is. For most of them, “pressure plate” would work.

Make paranoid trap not a universal option, but tied to gear: certain “careful” pieces of gear such as elven boots passively warn you of known traps before you step into them.

Alternatively, add a ring of paranoia which enables the paranoid warnings for traps and liquids. Or simply add this functionality to the ring of warning.

Rangers have a lower chance of triggering a trap they created themselves, since they are supposed to be pretty experienced in laying traps for creatures and not triggering them.

Artifact ring of searching that protects you completely from triggering a trap you didn’t already know about.

Various types of floor traps trigger based on your weight. This makes the trap more likely to trigger on a heavily armored character or one who has collected a lot of loot. Would work nicely in the Gnomish Mines, since gnomes are light and don’t tend to carry much stuff. Certain traps could also trigger to a lesser degree if you weigh enough to trigger it but not a whole ton.

Traps track the turn on which they were created in the trap struct. This is used to determine the age of a web; creatures will tear through an older web more easily, and with less strength, than a young one.

(Possibly, when you spend time off-level, this trap timestamp updates to account for that time, because time is frozen when you aren’t on a level.)

If teleportation fails because there is a trap or monster on the destination square, and there is an adjacent free square, you get placed on that square, possibly with a message explaining why you didn’t end up exactly where you wanted.

All demons are automatically aware of all traps in Gehennom, so they won’t walk into them and trigger them.

A potion or spell of searching: it doesn’t give you the regular searching intrinsic, but rather it detects any traps you move adjacent to with a 100% chance (regular searching isn’t guaranteed to find these, and this effect won’t find other things that searching is able to find).

Alternatively, just make it give you temporary intrinsic searching as currently implemented, but make it so that timing-out intrinsic searching (available only from this) is guaranteed to find everything.

When you try to move onto a known trap with the m command, the game interprets it as you specifically trying to avoid the trap you already know about, and your chance of triggering it is greatly lowered.

Archeologists can apply their whips to cross over a ground-based trap with impunity, a la Indiana Jones.

When you are turning to slime, higher luck increases the odds of a container trap or magic trap being a tower of flame, and increases rather than decreases the odds of any tower of flame trap (container, magic and fire) hitting you.

Zapping a cancellation beam downwards while standing on a magical (magic, teleportation, polymorph, etc) trap will remove the trap.

Add two fields to struct trap: an object, which represents the “ammo” of the trap (darts, arrows, potions of oil), and a number to represent the “level” of the trap (which can affect a lot of things, such as a to-hit bonus the trap gets, how hard it is to untrap, or what the skill was of the player when they set the trap).

Rogues can build and set traps, more types of traps than just plain pits and land mines and bear traps. Traps may consume some types of items to be set, like a sleeping gas trap will consume potions of sleeping. This should probably not be totally reversible through untrapping. Intended so the player can pick their battles and set up traps in an advantageous position.

Determining whether you escape or dodge trap effects should be based on stats like Dexterity and maybe role and XL, rather than Luck.

Change trap symbols and colors to be more unique: holes should go on their own glyph, level teleporters should be colored bright magenta, trap doors should be colored green.

Several things relating to making the upper dungeon feel more “eroded” or exposed to the elements/other adventurers, in keeping with NetHack flavor that other people have been seeking the Amulet:

• Falling rock traps on shallow levels come “pre-disarmed”, which is to say that they have already been used up and so should consist of a pile of rocks on the ground underneath a falling rock trap with no rocks left in it.
• Rolling boulder traps on shallow levels generate without boulders or with out-of-line boulders.
• Traps with ammunition can have a few pieces of that ammunition lying on the appropriate space.
• Dilapidated armories.
• Monsters on these levels are likely to generate with zero-charge or low-charge wands or other items.
• Fewer items lying around.
• Randomly destroyed walls.
• Fake bones piles (see below).

Note that this has been partially implemented in 3.6.1 with the addition of fake bones piles that come with a pre-disarmed trap if applicable, although that was aimed less at adding ambiance and more at helping players avoid early traps.

Sitting on a trap should trigger the trap while ignoring any magic resistance you have, so that you don’t have to disrobe.