Dropping a thought here:
MTGJSON has token cards, and with the last release (5.2.1) there are also information on related cards.
The data should be from Scryfall as well. We could build the database automatically rather than trying to keep up manually, similar to our spoiler files.
For the future, once Oracle is not used anymore and there are ready-to-use, MTGJSON sourced card databases for Cockatrice, tokens can maybe be part of it as well.