Hard to speak about 'favorites' when it comes to torture
That Brusca-bit was ugly of course.

But other than that, a lot of hardcore bits have happened :
Glasgow crime boss Arthur Thompson for instance had a thing for nailing his victims to the floor if they couldn't repay their debt. This 'crucify' method is apparently very popular among British gangsters, since English, Irish and Scottish criminals have all been known for using this method.
Southeast Asian gangs also use some 'nifty' methods of torture on their home invasion victims. This includes drilling holes into their kneecaps, using stapleguns, almost choking their victims with a plastic bag,...
A couple of sick Serbian gangsters once tortured an informant with a hammer, slowly beating him to death, before they just fucking ate him. SICK
If you watch the movie El Sicario - Room 164, a former Mexican hitman also shares some disgusting methods of torture.

Torture is just disgusting