Møgsvin (filth-pig), used as an insult similar to "asshole" or for someone who is literally filthy or messy.

Ikke den hurtigste knallert på havnen (not the fastest moped on the docks), used to describe someone who is stupid.

Pis mig i øret (piss in my ear), similar meaning as "fuck off".

Svagpisser (weak-pisser), for someone who is squeamish.

Pikhud på fingrene (cock-skin on your fingers), for someone who is squeamish about manual labour or about touching hot objects.

Skidespræller (shitkicker), someone who is annoying and unserious.

Bonderøv (peasant-ass), someone who comes off as rural or in a more broader sense someone who is uncool or uncultured.

Klaphat (clap hat), synonyms with idiot. Refers to a type of hat worn by football fans in the 1980's featuring a pair of stuffed hands that will clap together when the weather pulls a string.

Tölpel - a clumsy person

Hohle Fritte - hollow french fry/chip

There's "Nga Loe Ma Thar" in Burmese - Son of a woman I f-ed

Well, in french we have the simple yet effective "Enculé de ta race" and I just can’t translate it. If someone’s brave enough to do it, many thanks in advance.

We have curse stacking so it forms one big word. Godverdommemiljaardenondju. It's an ugly mix of dialect, French and Dutch, meaning something like "curse you a billion times in the name of God". And if it's only a mild inconvenience we only use a small part, like "dju" or "miljaar."

Well my native language is English and my favorite insult is “I hope you fall face first into a pile of shit with your mouth open”

Once i heard someone curse someone else out with "May cancer feast on the bloody spunk in your lungs."

Let's throw some west-southern german things in here!

Seggl: Just a general insult to someone but not too bad. On the level of 'idiot'

Schafseggl: Just seggl with the prefix sheep. Slightly more derogatory

Grasdaggel: grass-dachshund, same level as Schafseggl

"Fåntratt", litterally translated as "idiot funnel". Something you might call a silly person

I really like "paspalho" (pt-br) it's a light insult you can use with friends without hurting them when they do something stupid in a funny way

In Swedish I would maybe say

Kioskmongo - kiosk mongoloid - someone of very low intellect that knows the difference of right and wrong and still chooses wrong

Chipsmongo - chip/crisp mongoloid - someone of low intellect that would rather just eat chips, preferably in a sandbox with the whole bag emptied into the sand.

I like the French 'Balance ton porc'.

'Balance your (inner) pig' of 'Keep your inner pig' in check'

On social networks, beyond the feminist spheres, a call around the keywords #balancetonporc and #metoo broke the omerta and reports testimony ranging from daily sexism and street harassment to sexual assaults.

Dich haben sie bei der Geburt drei Mal hochgeworfen und zwei Mal aufgefangen.

When you were born, they threw you three times and only caught you twice.

In Italian when you can’t swear with a “vaffanculo” (f you) you can say “vai a quel paese” that’s “go to that country” And specifically in Milanese dialect you can also say “va a ciapà i rat” “go catching rats”

Argentina here:

"La recalcada concha de tu madre." The closest translation would be "your mother's pussy" but with added emphasis by the word "recalcada" which would be something like... uhm... super-copied? Yeah, don't ask.

"Chuj Ci w dupe" is very popular in Polish. Literally "(put) a dick in you ass". But it's not " fuck you" or "fuck yourself". That would be " pierdol się".

In Argentina, "Boludo" or "Pelotudo". It's very common to hear both, but the first one is like a little bit friendly, you can use it with friends and they'll accept it, but in the other face, "Pelotudo" isn't that friendly and it is regularly used to just insult, haven't found anyone that used that ironically.

Wurschtbesen. Somewhere between a Gfrast and an Oaschwarzn. But on the nicer end of both.

You fight like a dairy farmer!

Pok guy - Cantonese phrase meaning falling on the street (literal translation) or hope you die on the street/suddenly (as an insult)

Well, not really my native tongue but close enough. "Baap maral anhariya mai, beta ke naam powerhouse" literally means "The father died in darkness and the son's name is powerhouse." Used for overly ambitious people/ lying about achievements.