Presently I am running my sort-of Deadlands Reloaded game and my Ravenloft/Masque of the Red Death campaign. While I have no intention of concluding them within the foreseeable future, I am always thinking up what to run next.
These are things that are presently rattling around in my noodle. I also have different systems in mind of each.
-A fantasy adventure crawl set in a mythic fantasy realm lightly flavored of northern Europe, with lots of runes and forests and druids and pseudo-vikings. Also, cavaliers and witches.
Systems: OSRIC, D&D 5e
-A trippy ass 70's style D&D. Pointy hatted wizards and magical mushroom forests and stuff.
Systems: Swords & Wizardry.
-A modern urban fantasy/horror game about supernatural factions fighting over big places of power. Equal parts Feng Shui, Dylan Dog, and Nightwatch. Maybe throw in some Dresden Files and Iron Druid.
Systems: Cryptworld + Creature Feature + Majus, Fudge, Savage Worlds, Silent Legions/BXWOD