Use the below regex to find and and remove set names in .dec files for mtg card decks. Use Notepad++ to search and make sure the search mode is "Regular Expressions"; Leave the replace with field blank and you're GTG!
\s\[(?<SET>(?<VAR1>[A-Z]{3})|(?<VAR2>[A-Z]{1}[0-9]{2})|(?<VAR3>[A-Z]{2})|(?<OTHER>[0-9]{1,2}[A-Z]{1,2}))\]