The most obvious target would be extra combat spells, especially if you've adding on some mana generators from attacking (various treasure generators, Neheb, some dragons)
Whether played fairly doubling up hideous Eldrazi cast and attack triggers or for combos, this is a great card
card game you might've played in 2004 or 2019: You summon monsters, activate spells, and spring traps to clear your opponent's board (or keep them from building one in the first place), and then attack them until they run out of life points
Between these two decks, and the accessories I've touched on above, Shimmering Skies is really a fun, celebratory entry in this game that hasn't yet missed its mark at all
If a nonland card is discarded, put a +1/+1 counter on the creature that is Conniving
Controlling combat, forcing your opponents to keep the gifted creatures, and drawing cards in the meantime allows you to build a really unorthodox deck