Here’s my high rotation list of games I like to play (and GM) that are different than D&D 5E and sorted off the top of my head.

Symbaroum (Fria Ligan | Symbaroum) is an easy jump from D&D, and it shares some similar mechanics. You can play refugee humans, goblins, changelings, or ogres, paired with familiar classes. It’s a d20 roll-under mechanic, with plenty of options to set your characters apart, and corruption! Explore the old forest of Davokar. It is alive — and beware of the treacherous elves! Symbaroum is a dark fantasy RPG, and as brutal as it is beautiful with its bleak old landscapes and forgotten bad things. Tons of support and materials by Fria Ligan and online communities. You can even catch my interview with Mattias on Diceology. Symbaroum is high on my list for its fantastic setting.

The One Ring, either edition [The One Ring RPG — Cubicle 7]. A bit crunchy and a lot different than D&D. The One Ring will reward you with long-term play. Pick up The Mirkwood Campaign book, and you’re set for a marathon of adventure in Middle Earth. Complete rules for making journeys and seeking audiences with important folk. The combat is novel and tactical but more straightforward than D&D and, I’d say, grittier. Best Lord of the Rings feels game, IMHO. Massive amount of supplements and online support communities. Cubicle 7 is currently having a big sale of the second edition.

The Burning Wheel RPG — Great for long campaigns, but do take the elephant eating approach to learn the game. I have been playing this game since its first edition 100 years ago. It’s still my workhorse for playing a campaign fantasy game. It’s a significant departure from D&D mechanics, just as crunchy. It’s player-driven, character-focused — that means if players don’t come to play, there is no game. The default world is a Tolkienish one, but there are chapters about making your own world. I once turned the tide of the great Dwarf-Elf war and redeemed my oath-breaking Dwarf by taking on a suicide mission. It was a glorious death. There are a few other books in the set, but this one at @25USD is all you need to play. The online community is huge and extremely helpful, and it is supported in Roll20. The Burning Wheel HQ folks are kinda OK too! 😆😝

The Forbidden Lands — Fantastic exploration rules, modern mechanics, and built for sandbox play. You can play wolf-kin, goblins, elves made from rubies, and orcs. The land is recovering from blight, and you are among the early explorers of the aftermath. I run Forbidden Lands for my Into the Mad Lands games, a 40+ player West Marches game. FL rocks the sandbox game. There are rules for travel, base building, crafting. The monsters are Monsters and have their own rules for murdering players. This has been a weekly source of fun play for me. Fully supported by Fria Ligan with excellent Roll20 character sheets.

Honorable mention — B/X D&D. I use Old School Essentials — Necrotic Gnome. I’m also running this in West Marches mode, and it’s fantastic. It is made to be hacked, modified, house-ruled to your group’s tastes. I’ve got house rules for no initiative/simultaneous combat, and defense checks that move the NPC attack rolls to be player facing. I’ve taken the travel concepts from Forbidden lands and tailored them for B/X. The game does exploration and dungeon crawls fast and brutal! 10 out of 10 deaths were enjoyable! You already know the OSR fan-base is colossal.

So that’s my active playlist. I have run and played these games and will continue to do so. They have been easy to get new folks into. They deliver on the adventure experience. YMMV. (and I’m not getting any kickbacks from Fria Ligan or Modiphius! I could only wish!!)