Gavin Verhey used today’s episode of Good Morning Magic to dive into signpost uncommons in draft.
Multicolor cards were pretty sparse in the early days of Magic, but in Magic Origins, Wizards of the Coast (WotC) introduced the ten signpost gold uncommons. Each color combination got a card to show off what the color pair was doing in the Limited format and often enable players who have drafted mostly one color a signal to go into a certain archetype.
By looking at the signpost uncommons from Zendikar Rising, you can quickly see what each color pair is up to.
The idea worked out so well, they have continued using the signpost uncommons in almost every set since. On top of Limited ramifications, the cards give clear deckbuilding signals to newer players while also occasionally reaching high-level constructed decks with cards like Winding Constrictor and Rogue Refiner.