EquipCompare. Many have used it, many loved it. Then, Blizzard added it's own implementation. However, this requires you to hold the shift key every time. Not anymore! MoncaiCompare is a lightweight addon with zero overhead to bring you the comfort of the original EquipCompare using as much as Blizzard's own code as possible. Automatically showing comparison tool tips in the bank, at the auction, in your bags, when looking at quest rewards and when clicking item links.
TipTac is a tooltip enchancement addon, it allows you to configure various things such as changing the tip anchor, the font, the scale of tips, plus a lot more.
It can also show a special tip window for units instead of the normal one, which allows for extra customization, such as having it show buffs, debuffs, health and mana bar, this can of course be disabled if you prefer the normal tip.
Very lightweight tooltip addon that seeks to modify the default tip instead of replace it. Features:
class-colored border for units,
added target text line,
"faded" tip if unit is tapped, dead, or offline,
custom border, background, and status bar textures,
ability to move the tooltip or attach to cursor,
health percentage shown on statusbar,
health bar moved inside tooltip,
item-quality colored border for items,
raid icon display. Configured through the Lua code.