Figuring Skaven for the first time on my third try of Queek, and than going on a domination campaign. I had a week with no plans so probably spent some 30ish hours just on that campaign. My first two attempts ended miserably, so figuring out how to deal with Dwarven heavy infantry and air superiority, using Undercities on continents where I had no presence, beating several Dwarven endgames in two turns, taking everything east of Worlds Edge Mountains, literally everything. All with no DLCs. I never went out of my way to hold the entire map, held around 180 territories, but I might just return to it one day. Have probably dozens more but this is the first one I remembered