When GW blew up the old world, KoW was suggested (by Matt, now on RC and co-author of v3) so my empire army got used as KoM (plus a few run-outs as rhordia as I had demigryhs, a steam tank & organ guns).
They then all got multi based, plus various other units got added. I slowly built up a stock of little allied contingents (4-500pts), of which the dwarves and Varangur (now NA) all became full armies.
Some Amazon vouchers from work, finding a cheap abyssals army set and being inspired by Dan Read’s basilean army lead to the next weird and wonderful creation.
Leftover scenery from that, lots of random historical models and re-purposing some of my original empire army created KoM army number 2.
More random stuff (camels!) plus lockdown meant I got round to doing something Arabian Nights style for KoM army 3.
Elves/trees are up next, an actual halfling heavy list planned and want to do a viking-esq Varangur army (the old one was more barbarian style), partly inspired by the Last Kingdom series of books I’m ploughing through!
I did medieval history as a degree (with mathematics!), a dissertation on early medieval warfare always like historical stuff, so human armies tended to be my go to - there are so many great/cheap/varied ranges out there.
Actual ability on the table is mainly secondary - none of the armies have ever been planned around lists or usability in game, but usually finish mid-table regardless!