Planescape used a variety of different things to active portals in Sigil (and elsewhere in the planes) ranging from the mundane (a rusted key) to the metaphorical (the bottled sigh of a forgotten hero).
What are some other good planar portal keys?
(IIRC, there isn't an official list; it was pretty much GMs discretion)
1. The final acorn from a dead oak
2. A leaf from Yggdrassil
3. A cobblestone from an endless street
What are some other good planar portal keys?
(IIRC, there isn't an official list; it was pretty much GMs discretion)
1. The final acorn from a dead oak
2. A leaf from Yggdrassil
3. A cobblestone from an endless street