Regulation marks are little letters which indicate whether a card is tournament eligible
Yes, Boros is the classic version, but its an upside you cant get away from with Ardenn, Intrepid Archaeologist and Rebbec, Architect of Ascension working so nicely together
Meanwhile, Rowan, Scion of WarRowan, Scion of War turns the life loss into a potentially absurd amount of colorless mana, allowing you to cast as many spells as your black and red sources allow
Unfortunately, theres nothing you can really do about that because some types dont exist in the TCG for a variety of reasons notably, to keep the TCG simpler and playable, because 11 Pokemon types are much easier to manage than 18 different ones that all demand different energies to play their movesets