Dark Contract with the Gate has this limitation, meaning you can only activate this effect to add once per turn, but you can add as many copies of Dark Contract with the Gate as you want per turn, so long as you only use the adding effect once
Being able to grab two evolutions in one go is the kind of effect that can snowball fast, especially if youre running builds with cards like Magnezone or Copperajah as finishers
This is often written in terms of binomial coefficients as: This is most easily interpreted as N choose n i.e
Other digital TCGs may try and riff on the same concept, but the idea of collecting every single type of monster is so deeply ingrained into the DNA of Pokemon that it's hard to imagine imitators feeling as rewarding to play
With synergies for +1/+1 counters everywhere, your board will grow out of control
Bubbling Muck is the black High Tide