Several potential additions for the clerical spell school:

• Bless: this could either be a low-level spell that works like it does in D&D where it gives you a to-hit and damage bonus, or it could be a high-level spell that blesses an item. Possibly it could bless items when cast at Skilled or above.
• Sanctuary: a medium-level spell that effectively makes monsters treat the 3x3 area around you like a coaligned temple for a limited time, unless you take a hostile action which ends the spell.
• Command: Drop: forces a monster to drop its weapon.
• Inflict Wounds: medium-level spell that deals damage while being in the clerical school. Damage should probably scale with skill.
• Hold Person: paralyzes a monster (or more strictly, a humanoid); fits right in since enemy priests can already cast this.
• Silence: Temporarily stops a monster from reading a scroll or casting a spell. Not specified if this should be a debuff or create a region of silence.
• Dispel Magic: Removes magical effects from a monster or multiple monsters. May be of limited use unless added to a variant where monster magic buffs are significant.
• Freedom of Movement: Grants temporary intrinsic free action, allowing you to free up a ring slot.

Wielding Tempest, in addition to its existing effects, protects you from being paralyzed by lightning on the Plane of Air. Also, when its area-of-effect lightning effect triggers, fog clouds and gas clouds around the center of the effect are destroyed or blown away, “clearing the air”.

Red light, a y that has an explosion attack that causes paralysis. This is a reference to red (traffic) lights in real life making you stop.

(There could also be green lights whose explosion gives a temporary speed boost, and yellow lights’ explosion could be expanded to slow the target as well as blinding it, but since this isn’t harmful to the target it’s a sillier idea.)

Make shopkeepers more susceptible to being paralyzed or put to sleep than they currently are, so it is easier to directly but non-lethally steal from them.

Paralysis should halve your speed and give you a 30% chance of not moving on a given attempt, rather than just being “sleep but harder to resist and you can’t wake up”.

Paralysis only freezes you in place on a square; it doesn’t prevent you from attacking and taking other non-movement actions.

Add a spell of paralysis, which basically copies the same monster spell. Melee range, better than sleep.

Applying a blessed whistle (either type) will unparalyze pets in range.

Ghosts lose their physical touch attack in favor of a reusable attack that scare-paralyzes you. Possibly, if this is unflavorful due to it just being the same ghost, change their AI to make them turn invisible after a certain amount of time being visible and not next to the player. Then they path towards you, and if you either stumble into them or they are next to you and get a move, they turn visible, paralyzing you. Since the actual action of them appearing out of nowhere would be what frightens you, see invisible would negate the effect.

Skeletons, or any monster with the MS_BONES sound, should rattle their bones periodically, which frighten the player into helplessness for a few turns.

New monster: green cube, which combines the abilities of a green slime and gelatinous cube: both sliming and paralysis.