Angel of angst: Every monster you kill requires you to sit through a randomly-generated bad poem.
Angel of breakdown: Guns have a 2% chance of jamming or misfiring per time used, permanantly ruining the gun.
Angel of D&D: You get +5 HP per level, +1 to hit per level, and +5% to dodge every other level. You get one trait at chargen, and one trait every three levels.
Angel of deaf: You don't hear monsters or gunfire.
Angel of disease: You're dying of cancer -- as long as you're dying, why not take a few demons with you? Your max HP goes down by 1 for every 1000 moves, to a minimum of 1 plus whatever you get from ironman.
Angel of escape: You're fighting up to the surface. You start with red armor and the BFG fighting the cyberdemon, and have to make it to the surface with ever-weaker weapons and limited supplies of ammo for your best weapons, while more and more former humans come against you...
Angel of fire: Every tile you step on becomes lava. Backtracking causes the normal damage.
Angel of hallucinations: The game randomly assigns a new 'psychadellic' monkier (and new color/symbol) to every monster, weapon, special level, etc., at the beginning of the game. You have no way of knowing what a 'monkey launcher' is until you fire it (is it the BFG or an advanced pistol?), and the 'menacing clown' (represented by a bright yellow c) might be the Cyberdemon, a Baron of Hell, or a former human.
Angel of mutation: Every level, before you select a trait, one trait you have already selected becomes a level in another trait.
Angel of niceness: You're pretty much Piffany. You heal 1 HP/turn, and monsters have a 50% chance of not attacking any turn they have a chance to. You can't attack OR use weapons. You win by hugging the Cyberdemon (getting in melee range).
Angel of noise: You have a rock-n-roll soundtrack following you. All monsters are automatically aware of your position whenever you enter a level.
Angel of nukes: You've been ordered to clear out Hell, no matter what. Every time you enter a level, a nuke is dropped and armed, with a suitably long countdown (250 or 500 turns).
Angel of overkill: When you kill a monster, you automatically fire one more time at it (if you have ammo), just to 'be sure.'
Angel of ricochets: Bullets that hit a wall bounce around until they strike something (up to 10 times).
Angel of sanitation: You take damage when you step on blood or corpses as if you had stepped into acid.
Angel of senility: You're pretty much the army's LAST hope. You lose 1 XP per turn, unless you'd drop a level.
Angel of shrapnel: Using explosive weapons on ammo causes random shots to fire, or (in the case of power cells and rockets) secondary explosions.
Angel of sniping: Your sight range is increased by 5. If enemies are close, your to-hit roll takes a (6-distance) penalty. (Aaah! Demons and lost souls! Geddem off me!)
Angel of superspeed: You move twice as fast, get two chances to dodge attacks, and attack in half the time. You may only attack in melee.
Angel of telepathy: You always know where the monsters are, even if you can't see them. The problem is, whenever you kill, you are stunned for at least 1 turn (more if you killed with excessive overkill...).
Angel of vitality: You heal 1 HP/turn. So do the monsters. Finish them off fast, because if you sit around using Cateye, you'll waste all your ammo only to have them heal, leaving you having to punch them out...