Smithing:
max mods seem to be (+9,+9) [DV+3/DV+6,0/PV+4]
chance to improve non-weapons above max: 1/(4DV) ,  1/(4PV)

Drowning:
Chance not to drown = items+luck-curse
where items = {ring of the fish, armor of the sea} give (100%,80%,60%)
waterbreathing fully bypasses this

catlord:
first some weird stuff, prolly setting coords
hostility: catskilled=0, catskilled<4 or catskilled>=5
+10hp for each cat killed
+1 level for each 25 cats killed (max level 20)

wands of far slaying:
(2,3,4) * pp + level + 30 seems right, damage is 1d6

statmodifying items:
there seem to be X different versions of items that by default give +X to a stat
at least there are 4 different bracers of toughness, 10 different black torcs and 12 different gogs

42 teleports required for descending the dusty dungeons. use teleport traps far away from the stairs.
250 teleports are required if you use the teleport effect from the stairs.
2000 turns required for librarian to talk. during this time you must not fail any stealth checks or talk
to anyone except the librarian (while inside the library) this means: have 100 stealth before you enter

characters with the raven starsign get the rune-covered trident at level 16
others get it at level 36

when entering darkness there's a chance to get the warning about grues.
doomed characters get killed on the next move in darkness 1 of 50 times.
other than that there are no effects.

when the chaos orbs are used they corrupt for the following amounts:
mana:  5000
air:    500
fire:   300
water:  600
earth:  300
wearing the elemental gauntlets *halves* this for all orbs and is strongly recommended

dipping in potions of raw chaos will not make wands of wishing or rings of djinni summoning

dipping wands:
booze: 2d2 1d3 1d2
boost mana: 3d3 2d3 1d3
mana: 3d4 2d4 1d4

reading:
scroll of charging: 3d3 2d3 1d3
scroll of chaos resistance: 100d30 100d10 -100d5
scroll of danger: 1d2 2d2 3d2
scroll of peace: 3d2 2d2 1d2

drinking:
potion of cure corruption: 50d30 50d10 -50d5

eating:
pepper petal: 6d10 3d8 3d4

using:
spenseweed: 5d4+20 3d6+3 1d6