As someone who is striving to complete such missions and hasnt been lucky enough to complete more than one of them just yet, the below list of Secret Mission conditions is provided by the folk over at Pokemon Zone
Maybe you can even include cards that pay you off for these tokens in your deck, like Aura Shards or something that sacrifices the spirits for value
When an activated ability is countered, it means that it doesnt resolve, it doesnt work
Cards with printing errorssuch as missing text, misaligned artwork, or inverted color schemeswere produced in very limited numbers and are regarded as unique collectors items
It is especially fine if you are using Mental Misstep to stop something from happening in a critical moment: the Vapor Snag or Gut Shot that comes at the inopportune time, for example
Most sets that featured Trainers Pokmon were purely comprised of them