For me, way back in the early times of 2015, a friend mentioned how much she loved playing Call of Cthulhu in college. A group of us now adults decided we’d try and get a game or two together, and I somehow became the Keeper. In an effort to get myself up to speed on DM’ing (after a looong dry spell) I started listening to Actual Plays, and at the time, the biggest one was RPPR.
At that point, they were adapting Chaosium rules to Delta Green a bit, but there was also bubbling interest in the re-release of Delta Green by Arc Dream. I was focused on CoC content, but I very quickly got into the DG stuff they were playing. I barely missed the original Kickstarter but have made it into all the rest and have a little bookshelf I’m proud of.
How about everyone else?
My DM had some 5e burnout and wanted to try to run some other systems, suggesting both WHFRP 2e and Delta Green since they’re both fairly simple d100 systems. We decided that since we have a few players that’ll be fairly regularly missing sessions, that Warhammer would be our “default” group game with a party that has an overarching story, with Delta Green serving as a sort of casual one-shot/mini-arc game where we make multiple characters to team up in the absence of other players to deal with the horrors around the world that the government doesn’t want us to know about for our own safety. I currently have an Archaeologist/Anthropologist/mythology nerd buddy-copping it up in northern Norway/Finland to investigate a missing persons case after our lead on a Troll turned out to be crazy people being crazy and accidentally running into a The Thing reindeer that bit a hunter, while a retired-Firefighter-turned-handyman is trying to keep a 15ft-tall shapeshifting beastman from brutalizing any more people in the woods of Arkansas and further traumatizing the poor rangers running the wilderness reserve it’s holed itself up in.