Do you guys use some aoc databases(like http://db.mmosite.com/aoc ) that collect data about quests, items, drop rates etc. to play this game? Any other good aoc database?

You can check this out, http://aoc.yg.com. It provides useful item information such as the stats, image, and even where you can get it.

Example of an epic item and its drop location Aegis of Five Mercies.