- The barber's chair - the City to Wermspittle (Trey, From the Sorcerer's Skull)
- The ornate painting - to the Sea of Stars (seaofstarsrpg)
- The Gem of Muktra - to Zalchis (garrisonjames, Hereticwerks)
- The Synchronocitor - point-A to point-C (garrisonjames, Hereticwerks)
- The corroded metal plaque-like thing - unknown... (garrisonjames, Zalchis)
- The Weak Points - to and from Wermspittle (garrisonjames, Hereticwerks)
- A Tenebrous Scarlet Portal - many, various... (garrisonjames, Hereticwerks)
- The Aeonic Synchropore - possibly to the past (garrisonjames, Hereticwerks)
- The Aquaducts of Xembor - outwards, across alternities (garrisonjames, Riskail)
- The Lunar Gates / Lunar Mansions - also into dreamspace (garrisonjames, Riskail)
- The Anagogue; The Whirlpool Gate - into Imperial space (John Till, Fate SF)
- The Maelstrom - to one of eight places (garrisonjames, Hereticwerks & Porky)
- The Dryad's Saddle - to another world (C'nor (Outermost_Toe), Lunching on Lamias)
- ...
- The First and Last Die - to other realities (Porky)
- The squishy cocoon - to dark and nasty regions (Porky)
- Confirmation of the Higg's boson - one here to others (Porky)
- The little helpers' dust - one here, maybe, to many others at once (Porky)
There's more inspiration at the original post and in the portal list, and if you need a spark for the world an open-ended portal might have as its destination, you could try this table.
Update: We've got so many in there now an alternative presentation may be needed.
_
Update: We've got so many in there now an alternative presentation may be needed.