In the last few days, I restumbled upon some very niche rules that I always forget about.
So as an attempt to write a good collection, but maybe also teach and learn stuff from other players, here is my current list. Feel free to add your wisdom
1. BLUDTOPOWA has a standard health to 3 tile rate of 3*level. For the sorcerer, this is 3*level + 4 (to counter the mana to health effect)
2. IMAWAL creates a pile of 1 gold (2 gold with black market) below the statue. ENDISWAL or PISORF there and the gold is yours! This does not happen, if you use IMAWAL on an empty tile (which is also easy to forget to be possible). This pisses off Binlor, but can be quite useful for dungeon generation and relying on Knockback damage and for blocking wall formation in Shifting Passages
3. Using IMAWAL on a slowed target gives 1 XP
4. If you block the complete attack of an enemy via damage reduction, corrosion and Frost does not get applied. This is especially useful with Taurog Shield against The Indomitable with 3 attack and 50 corrosions Also, getting 0 damage does not anger Tikki Tokki, regardless of the number of attacks.
5. It is possible to deal damage to enemies with Unholy Aura (lose piety on hit) without triggering the effect by PISORFING other enemies into them. In contrast, Riposte triggers on indirect hits.
6. Indirect Knockback dealt by the player being knocked back by a monster can damage Pacifist enemies with it ! You can also use knockback to damage pacifist enemies with a cue ball. But you can't kill them as knockback damage don't kill.
7. Wurrgarbl is a very good find when you prepped the Codex, because the burning stacks from the sword are immediately maxed too.
8. Getting TT's punishment gives First Strike ON TOP OF the slowed monsters.
9. When the Gorgon has lifesteal, her deathgaze attack can absorb life beyond the monster's health left. (Probably a bug) Actually lifesteal + deathgaze has some problems, and sometimes the 'wrong prediction box' can lead you to death.
10. If the Vampire becomes no longer at full health by increasing max health, he can generate mana with exploring. (Also, probably a bug)
11. Half-Dragon's knockback attack IS physical, but in the terms of Specialist badge, it is not physical (nor magical). Therefore the Half-Dragon always get the badge if with no PISORF.
12. If you tried to trigger body pact by hitting from a monster without having enough piety, the effect does not trigger. It's perfectly normal - but you can no longer trigger it from that same monster by any means, even if you try again with enough piety.
13. Patches random teleport does not take you on a 'special' square, such as stairs.
14. Thief's "+33% items" trait applies also for the gold piles, shops, and glyphs. But not for apothecaries.
15. If you attack a Manaburn enemy with an active Schadenfreude, you are mana burned but still get the mana. Can be useful for a last ditch effort
16. Using CYDSTEPP pisses of Dracul, not the actual usage of Death Protection like Tikki Tokki. This allows Namtars Ward to be used at full extent while worshipping Dracul
17. The Translocation Scroll does not break Miser
18. If you're a Paladin you can convert Taurog's gears without being punished.
19. If you kill a monster that Blinks and has Knockback, they will knock you in an unexpected direction.
20. Coward and Blink only trigger if the enemy is next to you. In particular, an enemy with Knockback and Coward will not flee if he pushes you away.
21. Sorcerers Magic Shield is a second magical attack that can strip another DP, but after the enemy hits
22. Assassins Strike against low level enemies does not trigger any enemy on hit effects, but all player on hit and on kill effects. Thus, you still get cursed and unstable enemies explode, but riposte does not trigger
23. If there is a pacifist enemy present on the map of same or lower level as you, you will be able to take GG's absolution and this will NOT remove the pacifist enemy. This allows you to take the boon any number of time (as long as you have enough piety and inventory space). I guess it's a bug.
24. Chemist in Mana Form can still regenerate health with Bloody Sigil.
25. Sorcerer takes damage from Fireball Retaliation before getting health from Essence Transit. (Not logical, but rarely matters much)
26. Sorcerer with IMAWAL generates only 6 health when casting it on an empty space.
27. Casting IMAWAL on an empy space with free cast from Dragon Soul doesn't generate mana.
28. An enemy can run cowardly away from a sorcerer twice due to the mana shield even though it was one attack.
29. An enemy will run away from you even if you deal no damage to it (monk with 0 damage is very easy to achieve)
30. The Wizard's BURNDAYRAZ counts as a free glyph, so you get 6 glyph per dungeon in total
31. Binlor does not hate you levelup beyond 10, but GG likes it
32. Warlords damage is calculated after being hit, unlike weakening
33. If you have Binlor's Stone Form and get knocked through a wall by an enemy with knockback, you will instantly gain Might for that wall being broken before damaging the enemy
34. If you get knocked back so that you will explore, the exploration will heal the monster only if you strike first.
35. If you are in a room that has no empty spaces and cast WONAFYT, the spell swaps you with the monster it summons like WEYTWUT
36. Gorgon's amethyst stare ignores weakness, so the strength of the death gaze may be different from the base damag
I will continue the list when I can think of more or with your added comments