Riot lets you pick whether you want your creatures to come into play with haste, an important mechanic when it comes to pushing damage through, or a +1/+1 counter on them when they enter the battlefield, making them bigger and synergizing with cards like Doubling Season
Then if there are twenty or more cards in your graveyard, you may play the exiled card without paying its mana cost
Contingency I spoke about how I really enjoyed playing the likes of Remember the Fallen and Animate Dead in my Syr Gwyn list, and with Reconstruct History, theres now more reason than ever to run a greater variety of spells
but "just" killing a creature two-for-one was its most common role
Im about out of words for the week, but I also want to give a mention to Praetors Grasp (already expensive, could get even more so), Fallen Shinobi, Nashi, Moon Sages Scion and Silent-Blade Oni (ninjutsu goodness for the top of their library), Thief of Sanity (more flying and stealing) and Mnemonic Betrayal (the Yawgmoths Will for their yards) as more cards that could see a significant spike in coming days as Tasha begins her non-benevolent reign over all
White-Blue Artifacts This deck is somewhat self-explanatory as it's primarily a two-color deck centered around artifacts and payoffs for playing artifacts