Lately, I’ve been thinking about whether I should start publishing more stuff beyond my musings here and my game sessions. I wouldn’t do this for the income stream (“monetize your hobby and make it a job” doesn’t appeal to me) but rather for the fun of seeing other people use what I’ve made and hopefully enjoying it themselves.
One of the things I’ve always appreciated about the OSR is the emphasis on making what you think is cool rather than what will “sell”. Maybe that’s a zine, or maybe that’s a fun set of random tables, or maps, or whatever. I’m less interested in adventures that give a specific hook, a railroaded story, and a set ending, or something close to that. That said, I have a few “adventure sites” I wrote for previous campaigns that I will probably publish in one form or another, because you should be able to drop those wherever they fit in your game.

This isn’t really specific to the OSR, of course; just look at the list of games Powered by the Apocalypse, or all the hacks where people create moves and monsters and house rules. All those things are way more interesting to me than a book of pre-written adventure, because then you’re not really playing to find out what happens.
Oddly, I never look much at character options. In D&D 5e, for example, if a player wants a custom subclass or something, I look to make sure it seems relatively “balanced” (meaning “won’t make everybody else feel irrelevant”) and fits the themes or aesthetics we’re trying for. And even if it doesn’t, that gives me a signal about what that player wants in the game, so probably instead I need to adjust my expectations so that we’re more collaborative.
My next short campaign, “From Us Came Dusk,” will use the Homebrew World hack for Dungeon World. Very little is created in advance, but the players all have bought into focusing on a world with aesthetics reminiscent of Breath of the Wild and Horizon Zero Dawn: a lush, green world set far into a post-apocalyptic future with bits of tech that no one understands. (It’s not unlike Numenera, either, I suppose.) We’re going to play for four weeks on Tuesday evenings on Variant Roles, and other than the experience itself, what I want to come out of this is more DW stuff: some items, maybe a few monsters, a custom move or three, etc. Hopefully other GMs can take the artifacts from my games and drop them into their own, because ultimately that’s why most of us do this stuff: not to contribute to some corporation’s intellectual property asset list, but to make and share and enjoy.