[Edit: I changed out one fantasy game for another, as I concluded that I preferred the more streamlined system of Vagabonds of Dyfed over the more complex, move-based system of Freebooters on the Frontier 2e. 4/27/21]
Recently taking a moment to reflect, I've found myself hip-deep in middle-age. It happens to a lot of us. I realized that, in a likelihood, I've probably got as many games ahead of me as I do behind me. (It's possible this is inaccurate, as I did take ~20 years off from RPGs, but in the interest of an introspective post, let's just roll with that estimate.) I looked back at past campaigns, thinking, They were numerous, but the variety of RPG systems across them was very limited. Like many RPG hobbyists, I tend to collect a lot of game systems -- but, if I'm being honest with myself, there's not a very high chance that I'll actually spend much time (if any) playing those systems.
Admittedly, it's fun to simply collect RPG rulebooks, even if you're not going to necessarily play them all. And, if you're like me, you also get enjoyment out of reading them and expanding your awareness of the variety of rules and mechanics across the hobby. But, that's not ultimately why we're here: we're here to play or run them at the table. So this pause for reflection got me reading. I decided to read through all the rulebooks that I owned (in some cases, it was a quicker read, closer to skimming) so that I might identify my personal "core" games -- those that I turn to as favorites and that I'd be most likely to enjoy running for others. I began a survey of my collection to help me wrap my brain around exactly what I had, how each worked on the simplest level, and how much I valued each personally.