So I was playing violet, and I bought 10 calciums to use on my Lucario, but I had another one and I accidentally used eleven. How can I use 11 vitamins all on one pokémon?
[Starting in Generation 8,] Calcium can now be used even on a Pokémon that has 100 Special Attack EVs or more, allowing the Special Attack EVs to be raised to the single-stat cap of 252 or the total cap of 510 this way. This raises the limit to a maximum of 26 on a single Pokémon.
Calcium (Bulbapedia)
The same holds true for every other stat-increasing vitamin.
