Little Known Song Continuity Crossover: The song "Danny Boy" is about a boy who went down to the woods on the day of the Teddy Bears' Picnic
Most roguelikes already have a built-in specialising system in the form of limited item and weapon drops. 868-BACK and its predecessors accompany this (in this case, limited prog drops) with a diversifying system of 2 currencies that you must balance.
Interestingly, because you have easy access to both currencies in equal measure, the seemingly-similar 2-colour system actually serves the opposite purpose as it does in MTG.
Basically, each of these work to restrict your deck choices from different directions - to force decks out of a narrow category (card names) but to stay within a broad category (card colours) - to pen them into a middle ground of overall diversity.
I've been thinking about how card games and card-game-adjacent roguelikes tend to have two kinds of counterintuitively opposing systems - "diversifying systems" that force the player to diversity their moves, and "specialising systems" that force the player to restrict them.
The big example is Magic The Gathering - its specialising system is the 5 colour system that restricts your access to card currency, and its diversifying system is the 4-of-a-kind rule that forces you to have a diversity of card names.
I think it's funny that when a citizen is forced to do something by the government, it's called an order, but when a constitutional monarch is forced to do something by the government, it's called "advice".