A niche hobby even more obsessive than pen-and-paper RPGs in my estimation (since there's so much math involved), wargaming often has to do with alternate history. Avalanche Press has many AH scenarios that are amusing, my current favorite being the Byzantine Empire in 1939. A lot of these scenarios are nicely alluded to on their website.
What games, series, or companies dealing with wargaming have a lot of AH content?
What games, series, or companies dealing with wargaming have a lot of AH content?