Some subreddits seem to be created mainly for shock value, or perhaps to see where the Reddit staff draw the line regarding acceptable behavior.

    /r/niggers
    /r/picsofdeadkids
    //hotrapestories
    /r/RapingWomen
    /r/watchpeopledie
    /r/beatingtrannies
    /r/SexyAbortions
    /r/beatingwomen
    /r/popping
    /r/MorbidReality

Things taken down in ~March 2012

    http://news.cnet.com/8301-1023_3-57376256-93/reddit-bans-sexually-suggestive-images-of-children/
    http://www.reddit.com/r/blog/comments/pmj7f/a_necessary_change_in_policy/

        /r/picsofdeadjailbait
        /r/niggerjailbait
        /r/teen_girls
        /r/TeenGirls
        /r/pro_teen_models
        /r/preteen_girls
        /r/JailbaitArchives
        /r/JailbaitVideos
        /r/TrueJailbait
        /r/ChestyBait
        /r/bustybait
        /r/cutegirls
        /r/asianjailbait
        /r/JustTeens
        /r/JailbaitJunkies
        /r/jailbait_nospam
        /r/jailbaitgw
        /r/nudistbeach
        /r/Purenudism
        /r/teens
        /r/Thenewjailbait
        /r/trapbait
        /r/malejailbait
        /r/malejailbaitarchives
        /r/lolicon
        /r/shotacon
        /r/assbait
        /r/preteen_boys
        /r/photobucketplunder
        /r/AngieVarona