My recent "Modernisms" series focused on the false assumptions that can trip you up.
But on a tangential topic, what actual modernisms and anachronisms are in my Felltower game?
Gender Equality is a thing. No one treats women less well because of their gender.
Racial Equality is generally a thing - so much so that you get a whack of points back if you aren't treated equally and few people earn those points.
Universal Currency - not an anachronism, just a modern concerpt transported backward. Oddly everyone except the people who coined that King Gorillicus coin make identical coinage, and even that one is the same size and weight as the others.
Atheists exist. Seriously. In a world were clerics are demonstrably gaining power from supernatural beings, doing things wizards cannot, some people (mostly Vryce) don't believe that the Good God is anything other than an excuse for rules worshipped by mages with an alternate spell-set.
Modern-style Locks are definitely more than TL Olden Times. But they exist, complete with pins, tumblers, weighted mechanisms, and other very modern lock elements. Because fantasy gaming has that stuff.
I'm not really vouching for the fact that these exist, only it sure seems like they do.
Wizard Court might really be a thing. The Barcas swear it is, and non-mages are automatically guilty.
Scout College also might be real. Credits, semesters, homework, hazing, dorms (aka tree stands and hunting blinds) . . . it's all there. Even student loans to go to Scout College have come up.
Instagram might not really exist, but there is a #Felltower hashtag and accounts dedicated to posting about it.
I'm almost certainly forgetting a bunch . . . maybe my players will chime in?