A few insults the universe I play/run in uses. Some are racial slurs, some are not, some are relatively situational.
"Vilesoul" is an insult aimed towards Tieflings, Changelings, Warlocks- Generally anyone who dabbles in dark arts or has been born from some foul joining of Demon and Mortal.
"Pack Warmly" is a way of saying 'Go to Hell'- Given that in this universe, Hell is a freezing cold abyss.
"Warmother" is a harsh way to refer to the mother of Half Orcs, or any female who sympathizes with the Orcish race, who in-universe are almost exclusively kidnappers, rapists, and warmongering savages.
"Sandspitter" is a regional insult, used towards people from desert areas.
"Diplomat" (used as in 'Oh, yeah, he's a -real- diplomat.) essentially used to mean 'Race Traitor'- Someone who pursues romantic or carnal interests outside their own species.
More religious combatants often yell 'Rejoin the Cycle!' towards enemies. Basically telling someone to 'Fucking die, and rejoin the cycle of Reincarnation.'
Arrowpoint: Cockhead.
Dull arrowpoint: Stupid Cockhead.
Bent Arrow: Derogatory term for male homosexuals.
Stablemud: Shit. Referring to how often horses and other stabled animals tend to defecate, obviously.
Busy Gardener: A way of referring to a manwhore (or a promiscuous lesbian)
Cave: A way of referring to a promiscuous woman. Usually reserved for non-prostitutes. (Used: 'You're dating Suzie? Bring a map, she's a real cave.')
Busy Woman: A (female) prostitute.
Pet: A derogatory term for beast races. (Wolfin, Bird People, etc.)