Ah a finally found the "Conan of the Isles" ones I wrote down. Some of my favourites are:
Curses
"A pox to this business of ..."
"By all the scarlet fiends of Hell"
"By the scarlet bowels of Hell"
Challenges
"I still know a trick or two, which I shall be pleased to show you if you like?"
"You get past me you are free to do as you will - but you will find me no easy foe."
"Sheath your swords now and I will forget this incident. If you continue to attack, I will give you no quarter".
"This is no time to jape young man. Your life is forfeit if we continue".
Insults
"You lying, crooked dungheap".
"Filthy, diseased, son of a dozen unnatural fathers".
"You old barrel of whale blubber".
"...when you were still puking up your mother's thin, sour milk".
"...when you were still fondling boys in the back of a (place) whorehouse".
"Slink back to your fetid kennel".
"There are others here with more manhood in one hand than you have in your yellow-bellied body".
...and my favourite: "Girl-faced, fancy-clad, soft-gutted whelp of a nameless (place) gutter slut".
Other common terms used to degrade:
knave, dog, dullard, cur, gaffer, scum, swine, swabs, lubber.
As an odd side note: I am currently teaching Romeo and Juliet in English and in the unit of work I was given, guess what appeared? Yep, the Shakespeare insult generator. The kids love it and it is great to here them using other expletives than 'crap' and the current 'in' word at the moment 'gay'. I know it is lame, but go figure. A couple have instead begun to replace these with scut. Ah, so this thread is not only a very good and helpful one for GMs, it is educational.
Keep them coming. Connors