Certainly both of them will be relevant occasionally but they will be very hard to rely on for much
A deck focused on graveyard interaction, such as a red-black or red-green land destruction deck, would benefit from using Roiling Terrain due to its ability to both destroy a land and deal damage based on the number of land cards in the opponent's graveyard
For an MTG card size template that you can use yourself to create completely custom cards, MagicCube has got your covered
Its effect, loosely paraphrased, says that whenever an opponent casts a creature spell that doesnt share a color with creatures you control, counter that spell unless that player pays an additional cost
Sometimes that extra counter pushes you into ultimate range immediately, or quicker enough to be worth it, and with Atraxa you'll never run out of counters to throw around