Like anything else we discuss, playing with or for two-for-ones is just a tool
While we have more than enough actual slivers to choose from, there are a few changeling cards that might be considered: Mutavault, Shields of Velis Vel, Amoeboid Changeling, Blades of Velis Vel, Shapesharer, Mirror Entity, Taurean Mauler, Chameleon Colossus
Switching to the offensive with haste effects like Urabrask, the Hidden and Hammer of Purphoros can close games very quickly, especially after using recursion like Marshals Anthem and Sun Titan to restock your board
Other creatures you control enter the battlefield with an additional +1/+1 counter on them for each mana from a Treasure spent to cast them." The card is good for sure, but it's on this list because we feel as though it represents the way treasure tokens have evolved this year
This card doesnt necessarily warp formats or break the game, but it has that sort of all-around versatility that makes it such a staple in many formats