I've noticed a trend during my gaming hiatus....I'm back to browsing endlessly through Mythras and associated tomes, reading and scheming about what I might do with them. BRP remains a core go-to when it comes to Call of Cthulhu gaming, but Mythras covers all the bases so well these days, that its justifiably entered the realm of "universal systems" which the likes of GURPS and a few others normally hold the ring on. I mean....look at this breakdown:
Want to do Science Fiction? Mythras Imperative gives you essential tools, M-Space and its expansions carry it through.
Want to do time traveling or alternate realities? Check out Luther Arkwright, which aside from being a useful sourcebook on an interesting but obscure British graphic novel series is also a useful dimension-hopping sourcebook.
Want to do D&D but with a D100 mechanic? Classic Fantasy has you covered, providing more than enough emulation to incorporate classes and a ton of D&D tropes without otherwise altering the core Mythras experience.
Just interested in straight fantasy? Classic Mythras has all you need in its core book, but you can also dive deep into mytho-historical adventures in Britain, Rome, Constantinople and now Babylon. It is also trivially easy to pull any GURPS sourcebook as a reference tool for use with Mythras.
Pulp adventure? Monster Island is an excellent resource, and Mythras Imperative covers the bases nicely, although I think there is room for more here.
Post-Apocalypse? Rubble & Ruin and Seasons of the Dead collectively cover most any angle on the genre you could want. R&R covers a low key near future apocalypse with plenty of science-fiction weirdness (not Gamma World level, but you could definitely use this for a quasi realistic post-apoc future). Seasons of the Dead has everything from zombie plagues to terminator robot invasions fully covered, something I did not expect prior to getting the book.
Weird alt-reality dystopian retro-futurist Sci Fi? Odd Soot is one unique and dark flavor, and there's Worlds United for an entire other "Flash Gordon" style flavor. I have the former but not yet the latter.....I'm not much of a fan for retro-futurism unless it incorporates the benefit of hindsight, but concede I haven't picked up Worlds United yet so maybe there's stuff I don't know about.
If you want mythos stuff, and don't mind "Mythras adjacent" from the OGL we have Delta Green, and there are other similar mythos-based OGL products online as well (that I don't have so can't comment on). Delta Green is nonetheless the best modern interpretation of the Cthulhu Mythos out there, so well worth it.
Supers is covered too. 3rd edition Mythras Imperative contains enough rules to start, and a forthcoming tome from TDM will provide the rest.
I see some spots that need more bits to fill in, of course: a proper Pulp Adventures setting book would be nice, I imagine, for those who want to run some hardcore Indiana Jones type stuff. More SF content would be welcome; a Gear Sourcebook for Mythras and/or M-Space would be extremely welcome. We could also use some more focused genre books on Cyberpunk and maybe something aimed at modern day adventuring, or modern horror that is not typically mythos based.
The issue I face now is: how to narrow down the focus to what I should run next? I'm leaning hard toward something Rubble & Ruin on the one side, and of course Mythic Babylon on the fantasy side. I also have the Bronze Age Egypt campaign I've been working on, which would be easy to fit within the Mythras rules. After that....M-Space, Mythic Britain, and more all demand attention. Maybe I can plot out several 4-6 session long mini campaigns in different settings, and let the group decide which flavor they are most keen on pursuing.