Locking All the Insanity in a Single Room: Lumping the Most Explosive Character Types Together
The Suit. Some men were just born to suit up. I'm pretty sure that it's clear that Barney lives in Archer's apartment, and that Schmidt's original character description was just "Barney Stinson". I could point out that these three hitting the town together would be legendary, but that would be too obvious to bother stating. Barney ("How I Met Your Mother"), Schmidt ("New Girl"), Archer ("Archer").
The Anchor. Some people are born to drag everyone else down. If these three were combined together in one room they would crush the will to live out of every living thing within a mile, probably by doing a series of catastrophically stupid things that put everyone else in the show at risk, and alerting them with their trademarked high pitched whine. Dawn ("Buffy"), Carl ("Walking Dead"), Callie ("Battlestar Galactica").
The Mad Scientist. By the end of any given day, these three would either literally destroy the universe, build a race of murderous sex robots, or just wake up naked and slathered in LSD-laced cough syrup. It's really a toss-up. Walter ("Fringe"), Krieger ("Archer"), Baltar ("Battlestar Galactica").
The Zeppo. Television shows often like to hold up a character who is portrayed as the least competent, obviously least likely to ever have sex, stammering loser with no self confidence. That individual is almost inevitably secretly the most competent bad ass that the show has ever produced, and to drive the point home, usually manages to sleep with just about every female character on the show, plus half the guest stars. Put together, these characters would manage to satisfy the entire female population of North America, save the world repeatedly, and do so in such a way that no one else ever even knows that they exist. Xander ("Buffy"), George ("Grey's Anatomy"), Cyril ("Archer")