If you are a gnome and encounter a monster wearing stomping boots, they can stomp on you to instantly kill you, just like the hero is able to do to small monsters while wearing those boots.

Merge the clockwork automaton and gnome races: you are a gnome in a clockwork suit. You are able to leave the suit and wind it up instead of needing to find other people to do it. However, if the suit gets destroyed in any way, you have to play the rest of the game as a gnome (which is probably nerfed compared to the current gnome).

Allow tourists to play as gnomes, and they start the game in Minetown instead of dungeon level 1.

Gnomes, being much smaller than other races, hunger significantly less quickly.

Gnomes (or a potential Tinkerer role) can loot statues without destroying them.

Gnomes get permanent detection of gold and gems within a radius 3. Or possibly the radius can scale with XL.

Archeologists (maybe gnomes too) start the game with all valuable and worthless gems (but not gray stones) identified. If this is too powerful, perhaps they only begin the game with all worthless glass identified.

Gnomish characters read spellbooks faster than other races.

Gnomish characters get some interesting starting items, like tin openers, candles, oil, or cans of grease.

Reduce gnomes’ Str and Con caps, but ensure they get decent Dex and Int. They should be obviously different to play than humans (rather than being mostly superior). Dwarves should have a Wis cap of 16. Elves’ Dex cap should be higher than humans’.

Gnomes get a racial bonus using aklys and crossbow. Should probably be implemented by affiliating an item type with a certain race, adding this as a new object attribute, and only specifying it on racial items (elven armor, orcish weapons, the aklys and crossbow, etc.)

Make the Ranger quest artifact a crossbow if you are a gnome.