Limit: X

Limit: X is a rule that applies to some kinds of tokens. It means "If summoning the number of tokens indicated by an ability would cause you to have X or more of that kind of token in play, instead only summon enough tokens to bring your number of copies of that token up to X." — sharpo
You might still end up having more than X of a token in play, for example if you steal them from your opponent. — sharpo
When a card specifies that Limit: X applies to one way of creating tokens, that limit applies to all ways of creating that kind of token in the whole game. — sharpo
Limit: X on some kind of token applies to things that are that token before considering copy effects or Polymorph: Squirrel. So Quince's Mirror Illusion tokens will apply against his limit of 2 Mirror Illusions even if they are copying something else. — sharpo