Joran van der Sloot is referenced directly multiple times, and shares the killer's background of being a Dutch citizen in the Caribbean.
Oddly, the killer's horrible childhood is much like the horrible childhood of Jesse Pomeroy, a 19th century, American, underage, budding serial killer.
The killer giving his victims water bottles laced with rohypnol to abduct them was inspired by Erika Messer imagining what if that happened to her in a vacation.
"The Harmful One": Includes a passing reference to the 2014 murders of British backpackers Hannah Witheridge and David Miller, although the episode's case has nothing to do with it (other than also being in Thailand).
"Denial": Probably the most loaded, with direct references to the Arab Spring, Mubarak, the Muslim Brotherhood, terrorism in the Sinai peninsula, the use of deadly tear gas by the Egyptian police and the issue of gay rights and homophobia in Egypt.
"The Lonely Heart": Notably averted. Set in Paris, zero reference to Islamist terrorism.
"The Matchmaker": All about ISIS, down to featuring an unnamed expy of it. Most notably, the existence of ISIS's internet (female, western) propagandists and recruiters such as Colleen LaRose and the recruitment of Western teen brides like the Benthal Green girls and the Austrian girls.
The reveal that the smuggling ring is trafficking endangered dragon fish (hence the title) rather than drugs is likely ripped from stories about crime arising from demand for this species in SE Asia, such as this.
"Il Mostro": In 2014, a Romanian prostitute was found "crucified" in Florence. The testimony of other prostitutes pointed to a man in his 50s or 60s being responsible, prompting press speculation about the possible return of the Monster of Florence, a serial killer active in the 1970s and 1980s who was never apprehended. Unlike in the episode, this turned to not be the case.