Knights should be given a tame ki-rin from their god when they get crowned. Possibly only if they have enhanced their riding skill; a knight who hasn’t enhanced it probably wants some other gift. Since ki-rin are lawful, a knight who has converted to some other alignment and is being crowned by a non-lawful god probably should not be granted one.

If you are a chaotic Knight, Excalibur should evade your grasp, being impossible to pick up as if it were a crossaligned quest artifact.

(Additional rule for EvilHack: Dirge should evade the grasp of lawful knights.)

Getting crowned as a lawful character should unlock the ability to dip for Excalibur if you are currently unable to, or raise the odds for successfully dipping to what Knights get.

Lawful-aligned characters should feel guilty and incur an alignment record penalty in addition to the normal Luck penalty when they cheat in Sokoban.

Allow all lawful devils (or a random set of lawful devils) to accept a bribe, not just Asmodeus and Baalzebub. They will not vanish completely, but they will turn peaceful.

If you are polymorphed into a nymph and are lawful, you suffer an alignment penalty for stealing items from other monsters.

If a system is implemented that tracks the amount of booze you have drunk throughout the game, lawful gods start to penalize the player for drinking too much after a while.

Lawfuls get an alignment penalty for writing graffiti with a marker, even if it’s Elbereth or something else useful.