Though I guess I should add the disclaimer that I haven’t actively checked what alternatives were/are available to fill similar roles to the roles Metaforecast and Guesstimate aim to fill
The closest alternative I’ve found to Metaforecast would be The Odds API, which aggregates various APIs from betting houses, and is centered on sports.
More distantly and speculatively, I guess that Wikidata or fanfiction.net/archiveofourown (which are bigger and better, but just thinking of it conceptually) also delimit metaforecast, the one on the known-to-be-true part of the spectrum, the other on the known-to-be-fictional side.
The closest alternative I’ve found to Metaforecast would be The Odds API, which aggregates various APIs from betting houses, and is centered on sports.
More distantly and speculatively, I guess that Wikidata or fanfiction.net/archiveofourown (which are bigger and better, but just thinking of it conceptually) also delimit metaforecast, the one on the known-to-be-true part of the spectrum, the other on the known-to-be-fictional side.