Firefly - lets you see even if it is extremely dark. Equivalent of the "nightsight" skill in metamorphosis.
Moss - reduces bleeding when damaged. Essential, unless you have learned the survival skill "clotting".
Feather - gives the levitation defense. Silly for Sentinels because we get the levitation elixir so cheaply.
Shield - a shield that prevents physical attacks forms around you. Mental attacks will go through it, and it may also be hammered down with a hammer tattoo, or razed away with a sword (only knights).
Mindseye - allows you to see and hear even though you are deaf and blind. It is essential to be deaf and/or blind versus most classes.
Hammer - Use it to break someone's shield tattoo.
Cloak - prevents magical summoning by the brazier tattoo.
Bell - when someone spies on you, it rings.
Crystal - once per day (or is it month?) you may touch it and all your health is restored.
Moon - slowly replenishes your mana.
Starburst - instant resurrection when you die, with half the experience lost.
Boar - replenishes your health.
Web - spray webs over a person, restricting their movement until they writhe free.
Tentacle - drag someone down from the skies.
Hourglass - put someone to sleep.
Brazier - magically summon someone to your location.
Prism - magically travel to someone in the general vicinity.
Tree - touch it to cure an affliction. There is a time period between use though.
Chameleon - touch it and you assume the name of another player on the who and QW list. Useful for making enemies think you are not present in the realm.