There is plenty thats copyrightable in the game all the artwork, and the way its written but not the underlying rules themselves. Thus, Upper Deck, if the case proceeds, is arguing a breach of contract and fiduciary duty
"Dash [cost]" means "You may cast this card by paying [cost] rather than its mana cost," "If this spell's dash cost was paid, return the permanent this spell becomes to its owner's hand at the beginning of the next end step," and "As long as this permanent's dash cost was paid, it has haste." If you choose to pay the dash cost rather than the mana cost, you're still casting the spell
Being that reckless is a keyword, there will be likely be characters that have it organically, so we could see it used as a way to balance powerful effects
First up is Tactical Teamwork, an Amber/Sapphire deck that has two main play lines
Because resurrection plays a much more prevalent role in Lockes story than Terras, its surprising to see it on Terras card