Oh boy, honestly, I wouldn't know of Romania because the swearing here is pretty vile as it incorporates all forms of swearing and it includes embedded curses and could drag people dear and known to them(including those that passed away), depending on the anger threshold you breach on that person. Swearing is a national sport here and is deeply ingrained in our culture, and every form in the map from other countries is present.

What we may have extra than other cultures is that we include perverting religious ceremonies(Christian Orthoroxy, of course, as it is the major religion here), adding in saints, and could involve that person's children, dead relatives, involving universal extreme harm directed to that person, besides all the sexual connotations and God/Jesus'/the cross' wrath upon them. We even do chain-swearing incorporating all of them and could lengthen to a nasty curse ad infinitum, like it's some latin lenthy curse you see in movies. I won't give examples here because I may or may not break the rules, maybe ask your local romanian(as I'm pretty sure we're on every corner of te globe by now). But damn it really sounds horrid trying to explain the process and everything rationally, in writing. O_o

Maybe one as it is somehow benign involving feces and the baptizing ceremony "Sa ma cac in cristelnita ma-tii!" - May I shit in your mom's baptizing bowl, implying time travelling back in time just to take a dump in their mother's baptizing bowl during or before the act of baptizing. Over here... it's said that priests REALLY know how to swear as they know all the saints and religious practices. 😅

But what I could say is that you'd have to REALLY piss off someone to get to the most aggregious parts in the open. Though, if I were to pick depending on the regions, and reducing it between two common forms, the common ones are "God's righteus wrath to screw you over" in the west and east and "regulating your dead relatives/relatives/parents, phallic dominance, blowings" in the south, I would say though that the most common are the sexual ones first, as they are universal. Those that include a person's children in their swears are absolute degenerates and thankfully there aren't many that do so. Though it's a continuous exchange and the common thematics might switch constantly and there aren't too many studies on this(who the hell even studies swearing/cussing?)

Piss a Romanian off too much, they increase in intensity and if you happen to find one with a somewhat religious upbringing(not necessarily a priest), oh man... if superstitious about manifestating reality through words and stuff, you might get a PTSD.

P.S: You could look up "Inundatii bucuresti/flood in Bucharest", "preot injurand in aeroport ca nu primeste viza/priest swearing in an airport because he couldn't get a visa" to get a glimpse of how that may sound like, the latter is mega religious and chain swears like an animal.

Can't believe I am sharing cussing from zero in Romanian just to find out the most common swear words. In Romania, the hate is real, as you may as well see here... xD