Notably, because Boros Charm wasnt printed in the main MTG Foundations set, its recent reprinting didnt help supply much
Brawl Not Legal Vintage Legal Timeless Not Legal Commander Legal Pauper Not Legal Oathbreaker Legal Penny Legal Lackey Recycler Artifact Contraption Whenever you crank this Contraption, put target creature card from your graveyard on top of your library
Heal 30 damage from this Pokmon
Sure it has a sawblade for an arm, but it hardly looks out of place next to Skyfisher Spider
That aside, there's an extra point in the rules that states sponsors have the right to disqualify entries "not consistent with the spirit or theme of the Contest." Regardless, it's not been officially confirmed that this is the case or if it's the reason certain entrants have been removed from the Contest, so it might be a different issue entirely
Of course, you need to hold up protection like Force of Will or Deflecting Swateven one misstep in cEDH can cost you the game