And now, for your amusement and information: The Canonical List of Dibblers! (The name in parenthesis indicates their first apperance).

Cut-Me-Own-Throat Dibbler of Ankh-Morpork (Guards! Guards!), AKA Grand Master Lobsang Dibbler, Hubwards martial arts master with "an address in Ankh-Morpork" (Witches Abroad)
Solstice (Soll) Dibbler of Ankh-Morpork, yuppie nephew of Cut-Me-Own-Throat Dibbler (Moving Pictures)
Cut-Me-Own-Hand-Off Dblah of Omnia (Small Gods)
Disembowel-Myself-Honorably-Dibhala of The Agatean Empire (Interesting Times)
Al-jiblah of Klatch (Jingo)
Fair Go Dibbler of XXXX (The Last Continent)

Other Dibblers mentioned in The Last Continent:

May-I-Never-Achieve-Enlightenment Dhiblang
Dib Diblossonson (probably from Nothingfjord or something)
May-I-Be-Kicked-In-My-Own-Icehole Dibooki
Swallow-Me-Own-Blowdart Dlang-Dlang (Howandalandish, by the sound of it)

If I missed any, /msg me and tell me about it.