Aristophanes offers us plenty of Greek insults. Lots of them deal with feces, especially eating or shitting on others. Plenty deal with sex. Because Greeks compounded we have a lot of these that very directly translate into English, such as "koprophagos", "shit-eater" and "metrokoites", "mother-fucker", "kunops", "bitch (literally female dog)-face" or just "kun" or "kuna", "bitch" applied equally to men and women. The most common curse to a god is "ma Dia", "by Zeus", but you can find most gods' names in the accusative after "ma" for this like "ma Heran" or "ma Apollona".

Another one that Aristophanes uses a lot is "βάλλ' εἰς κόρακας" literally "Go to the Crows" but you could translate it however you want. Go to hell, Go fuck yourself, fuck off etc. etc.