The scenarios I’ve done were 10-15 in D&D, numerous parts to each of those and 10 in Talislanta.   there are likely a dozen others I’ve participated in and helped shape but for solid: hey, I think I made this. The number stands at, at least 25.  That I could roll out many more I have no doubts.

they were fun to come up with back in the day, why not now?  I feel the forces building to do so.  Which setting?  Whatever setting rolls out ideas the easiest, fastest, and funnest.  Do I write scenarios for players?  or written for the writer of the scenario?  kinda like cookbooks, which is better?  There is not much to replace a good dungeon master.  Sure 1000’s of options from predictable players can be taken care of by preestablished code and rules sets  but, ah, there are 1,000,000’s of possibilities I can conceive off the top of my head.  What is the permutations of options in current video games?  something on or the order of 10^100 more than likely.  But depends on the game and how it’s counted.  They might be fun.  A look at specific games permutations of game play options.  See if some patterns emerge such as best ranked games for a certain reason/reasons what they had as options of play.  Is there an upper limit to options? (skyrim and Bethesda games i’m thinking here)  Is there a lower limit? (tic-tac-toe i’m thinking here).

whatever the limits they are meant to be broken.  or at least tilted at.