Foundations Jumpstart (J25) and Special Guests (SPG) are Commander-, Legacy-, and Vintage-legal sets, and individual cards are also legal where already available in other formats
BT17-008 U Digimon Lv.3 Alternative Art Guilmon Color Red Cost 3 DP 1000 Digivolve Cost 1 Red 0 from Lv.2 Form Rookie Attribute Virus Type Reptile Card Text 1 [Effect] [Your Turn] [Once Per Turn] When any of your [Calumon] or Tamers with [Takato Matsuki] in their names are played, delete 1 of your opponent's Digimon with 3000 DP or less
We have a couple other powerful tricks up our sleeves, but Thumb is definitely the most important one
Nvm it's the bad one I forgot existed
If you are a personal collector who values detailed condition breakdowns, BGS is worth considering
Thats not too hard of a deal to make (especially since they get to draw two cards), but its something to keep in mind nonetheless