One of the playtest cards from Gavin’s unknown event was a card that referenced the MOM legendary team up cards; and he said that the card didn’t really work within the rules. Although that is technically true, I find it hard to believe it could not be easily worked into the rules. Obviously it is clearly understood from the average player POV, but from a rules perspective, why couldn’t there just be a section in the rules that lists all the cards that are legal options? That already exists for Apocalypse Chime, City in a Bottle, and Golgothian Sylex; and I would argue they are far less intuitive or easy to remember when it comes to what cards they apply to. This isn’t me demanding that Gavin’s card be made legal, more so it’s me asking: why can’t cards like that get made? Cards/mechanics that reference a small and intuitive list of cards, with the comprehensive rules having a formal definition for that list?

It comes down to how much stress does it put on the system and is it worth that stress? We believe the answer is no, because it’s a lot of stress for minimal pay off. That’s why acorn/silver-border cards exist. There are things that are practically easy to use, but are onerous on the rules system. Those cards should exist because they’re fun, but we can do so without causing problems with the larger rules structure.

If referencing expansion is acorn, why is Golgothian Sylex legal in eternal formats?

It doesn’t look for an expansion symbol, but instead references what cards were originally printed in Antiquities. It’s an awkward fix, hard to monitor, and not something we want to consciously do anymore (outside acorn where we can reference expansion symbols).

Hey Mark! Are City in a Bottle/Golgothian Sylex/Apocalypse Chime effects still black border, or have they moved to silver border like World-Bottling Kit? If they are black border will we ever see this effect again?

Black border can no longer mechanically reference expansion symbols.