So, I've written a couple... keeping a list updated is a pain but I'll give it a shot:

Addons on Curse-Gaming: http://www.curse-gaming.com/en/profile-502.html

    * AH_QuickSearch
    * AH_Reset
    * ArcanePartyBars
    * Archaeologist
    * AssistMe!
    * Better Item Count
    * ChannelManager (deprecated)
    * ChatBar
    * ChatClear
    * Chat Scroll
    * Chronos
    * FriendsFacts
    * GuildNotesTooltip
    * Gymnast Tooltips
    * ImprovedErrorFrame
    * IsCasting
    * IsMounted
    * LevelEstimator
    * Loot Safely (obsolete)
    * MenuOnScreen (obsolete)
    * Meteorologist
    * Mobile Frames
    * MobileMinimapButtons
    * ProfessionTracker
    * ReputationMenu
    * Sea
    * SeaHooks
    * SeaPrint
    * SeaString
    * Sky
    * Telepathy
    * TellTrack
    * TrackerToggle
    * Wardrobe-AL
    * WhoTip
    * wTunes Skin (deprecated)

WoWInterface Addons: http://www.wowinterface.com/list.php?skinnerid=18098

(ones not on cg)
    * ChatIgnore
    * Channel Menu
    * ConsisTint
    * Localization
    * ReURL
    * Satellite

Misc addons hosted 'somewhere' or maybe just in my head:

    * UniversalTranslator (obsolete)
    * MinimapZoom (In Cosmos)