Today, I run one campaign and one campaign only: Advanced Dungeons & Dragons, by the book. Character stables, strict timekeeping, training time, training costs, 0 HP bed rest, segments, system shock, unnatural aging, level caps for non-humans, encumbrance, spell costs, psionics, spell research, magic item manufacturing, domain play, the whole bag.
Twice a week, varying groups, open campaign, open table, open world, open rolls. My hope is that this shared world will persist for years, even as players come and go. That's the dream.
Since I returned to RPGs in 2020, I have run a few other games that went for at least a couple months.
We started with a Pathfinder 2e campaign that lasted until level 10 or 12, I think. By that time, most of us had concluded that the game was definitively not for us.
We then switched to Pokemon Tabletop United, which was engaging (despite disappointing rules discussions in the official discord). It was burdensome to run with five players.
Next up was Chronicles of Lastuynia, a Low Fantasy Gaming campaign. LFG is awesome, and my hard copies of the Core Rules and Companion continue to be valuable investments for their tables and modular rules.
After Chronicles of Lastuynia, one of my players ran a Star Wars Force & Destiny game for a couple months before we checked out the Unofficial Elder Scrolls RPG (UESRPG v3) for about 1.5 sessions before dropping it and making a nostalgic return to 3.5.
I ran a brutal 3.5 pointcrawl set in "the Outmarch," a land of my own making. One city of 12,000, Elberoth's Gate, with sea on one side and a deadly wilderness in every other direction. Mostly by the book, with a few house rules. In this campaign, I allowed every single official rulebook and supplement published for the game. I would not recommend it... more than once.
I ran an OSE Advanced Fantasy campaign set in Andrew Kolb's Neverland hexcrawl. The PCs were family members, retainers, or otherwise wards of House Dawnmourne, rightful rulers of the Kingdom of Eiovar. They traveled through a magic archway discovered deep within a mountain to Neverland, where they sought magic and wealth to grant Queen Elenor the power to stomp out the wars of the five other houses and regain monarchical control.
I ran the following systems as campaigns:
The following systems were only run as one-shots or short series, nothing more than a couple months in length I'd wager.
This list is certainly not exhaustive.