Attempting to define these is difficult, but think Model UN meets wargame meets roleplaying game meets wargame meets organised chaos.
I have played in around 40 of these to date and have currently two under active development, with various ideas as well. I hope to run both in 2027.
Mini Mega Monsters (adapted from the game by Bailey Nixon)

Mini Mega Monsters is a collectible card and economic management megagame about collecting cool monsters for your gym and using them to compete against other gyms!
Up to six gyms of up to seven Gym Captains and three Gym Administrators each will duke it out to collect the most monsters and secure glory to their gym! A team of Monster League Officials will oversee the matches, manage league-wide policies, and ensure a competitive meta while the nefarious Team Moppet will… Do nefarious things!
So join up to 70 other players and see if you and your friends can be the very best! The best that is right now!
Mini Mega Monsters is both a satire of and a celebration of the collectible critter-battler genre of Pokemon, Cassette Beasts, Beastiball, Digimon, and more, filtered through the lens of a competitive sports league megagame. Don’t worry, no monsters will actually be harmed.
(Credit to Bailey Nixon for the description)
Next Stop, Greenham Common

It’s the early 1980s and the Cold War is heating up. A Soviet build-up of nuclear and conventional forces is making many in NATO nervous, so the US attempts to negotiate an arms control treaty with the USSR… with new deployments of its own in Western Europe planned if no deal is reached. In a time of superpower tension and proxy wars, will attempts to protect the balance of terror instead bring about a global catastrophe?