Varying tech levels in fantasy. It's always some lame Medieval Times ahistorical mishmash anyway. Add better metallurgy. Gunpowder. Advanced clockworks. Just for variety's sake, at least, if not to open up new story possibilities.

Been working on a setting/story where decades prior unearthed ancient magitek from the ruins of the extinct elves started an overnight tech revolution, where they went from horses and swords and hand-crafted production to levitating airships and "mirages" (holograms basically) and wireless communication and death rays overnight, developing scientific modes of thought and of course having a series of increasingly large, horrifying, and apocalyptic wars, until splinter factions in the remaining slave armies of the mad kings that were left banded together to defeat and publicly execute their rulers and then continue a purge of all nobles, then clean up the mess and build a new kind of world without the Second Estate.

Hard figuring out how every society was affected by this without running away with it, but adds a good impetus for a band of misfits crewing an airship to have adventures in the exotic eastern continent, where the grandchildren of revolutaries are starting to invent colonialism and plunder more elf tech from ruins, and not let any scaly natives get in the way of profits. Sure, their weird exploding powder weapons kept invaders away before, but now the humans and orcs and goblins and dwarves and insectoids have lightning bolts in their pockets and there's purple magic crystals that power elf tech in them there hills, grandpa's orcish genocide flashbacks be damned