I Like Second-Stage-Randomness

There's probably a proper name for this family of mechanics but what I mean by second-stage-randomness is taking a base mechanic that is stable and knowable, and then spicing it up with a layer of random generation. Some examples:

Characters: Everyone knows what a Fighter is, how they work, and what sort of things they can do. But then we modify the Fighter by allowing some randomness in, so then two Fighters may look and act in different ways. Dragon Age and Shadowdark both do this with dice rolls to determine what abilities characters get, from class-specific tables, and I've tinkered with a similar idea myself.

Monsters: The room contains 1d12 orcish Morris dancers! But what if we can roll 1d8 to determine exactly what sort of orcish Morris dancers they are? 13th Age does something like this with its dragons, and there's a similar sort of idea here at I Cast Light! You don't want anything too complicated gumming up play at the table, just a simple modification to the standard monster to stop them becoming too predictable.

(If you're playing a Warhammer-style setting with true Chaos at work you could really lean into this with expanded tables for Chaotic creatures. Maybe even a d1000 table...)

Locations: I've been watching -- but not playing, I don't have the reflexes or time for that -- quite a bit of Nightreign the new Elden Ring spinoff. The game randomly generates some of its content, such as monster placement and type, so that while experienced players will get to know the general shape of the game, there is still some potential for surprises; you may know that it's one of six bosses over in that grove of trees, but which of the six you won't know until you get there. One other thing the game does is reshape the map with a special location that's randomly drawn from a pool; it could be a mysterious city, a snowy mountain, or a volcanic chasm. Players don't know which it will be -- if any; I think there's also a chance of none appearing and the map being "normal" -- until they arrive on the island.

It feels like there should be a way to do something similar in a tabletop role-playing game, although I haven't worked out how yet. You don't necessarily want randomly changing locations on your world map, unless you're using some sort of "chaos zone".

What I like about this sort of mechanic is that while randomly rolling everything can make a game feel arbitrary and meaningless, this gives a stable base but also accommodates an exciting layer of unpredictability. For me it's the best of both worlds, and you can even further adjust it by using bell curve probabilities to make things a bit more predictable.

But not too predictable, eh?