first edition unopened pokemon cards Episode 365 of Should I Open it? Or Should I Keep it Sealed? 1st Edition Pokemon Booster Packs

If the reasons you are wanting to play Thoughtsieze are entirely covered by another discard spell that doesn't administer pain then consider that instead

While theres nothing wrong with serialised cards per se, their limitation to collector boosters is yet another of Wizards of the Coasts fingers upsetting the scale balanced between game and collectible

You cannot normally cast things in your color identity, but with this, you can cast your foe's card draw, like Mulldrifter with evoke or Esper Sentinel

These changes go all the way back to the very first set, Alpha , and Jayemdae Tome

Which is very nearly true in this case