So far Iíve encountered these 36 distinct Tests of Faith. Havenít been able to find a list of them on the net yet so Iíve compiled my own, alphabetized them and reworded the descriptions a bit for clarity. Iím pretty sure that several of these occur only on certain difficulty settings and such.

Ally = Creature allies spawn near the altar (they look like enemies but have green stars over their heads).
Armor = You take less damage but your Rage (Ability) meter fills slower. (This is the opposite of ďRustĒ)
Arrows = Infinite ammo.
Bombs = Bombs rain from the sky (damaging both you and enemies).
Book = An added 50% XP for every kill.
Chest = Random goodies (Pickups & Gold Coins) spawn near the altar.
Coin = Blood turns to little Gold coins (both your blood and that of enemies).
Death = One-hit kill for both you and all enemies (you get a Trophy for this one!)
Dice = Your weapon changes randomly every 10 seconds.
Discord = Audio is weird (no effect on gameplay).
Drarfs = Enemies are smaller and weaker.
Emperor = A giant Gold Emperor Minotaur spawns and only dies once youíve killed all other enemies (but if you attack him he bleeds Gold Coins!)
Famine = Ammo slowly drains but new Ammo pickups spawn randomly.
Feud = Players take extra damage when close to each other (you will all have aura rings around you).
God Mode = You get random moments of invincibility and infinite ammo (same as the God Mode ability).
Grudge = Enemies attacks each other but friendly fire is also active.
Hat = All enemies are wearing hats (no effect on gameplay).
Last Stand = Your Health begins to decrease when you move away from the altar (there will be an aura ring around it).
Life = Your maximum Health is reduced to 75 but your Health slowly regenerates.
Lightweight = ďEnemies are light as a featherĒ (no real effect on gameplay).
Phoenix = Players explode when they die.
Poison = Your Health slowly drains but enemies are weaker.
Rage = Melee damage is increased plus you gain some Health for melee kills.
Resurrection = All players get 100 Health & Armor at the beginning of the Test plus one extra life is added to the pool.
Rock = You do increased damage but your Health decreases when you stop moving.
Rot = All enemies burst into a cloud of poison when they die.
Rust = You take more damage but your Rage (Ability) meter fills faster. (This is the opposite of ďArmorĒ)
Sanctuary = Enemies take damage when close to the altar (there will be an aura ring around it).
Shell = Your Armor regenerates slowly but Health Pickups do nothing (you canít pick them up at all).
Shroud = A very thick fog obscures your visibility.
Skeleton = Skeleton enemies are stronger and faster.
Thief = All static Pickups disappear until the Test is complete (but enemies will still drop them).
Titans = Enemies are bigger and tougher.
Trap = Mage seals randomly spawn.
Twins = Two giant Minotaurs spawn and must be killed within a few seconds of each other (or else the first one comes back to life).
Zombie = Zombie enemies are stronger and faster.