This type of larger deck size requirement is a very interesting mechanic in my opinion to shake up the design space a bit, posing a consistency/slightly worse card pool vs one extra card trade off
The plain white filler with black borders above is the most common filler
Nevinyrral, Urborg Tyrant + Piru, the Volatile These are expensive and awkward partial/conditional board wipes that are hard to cast
In the Cosmos, secrets swirl and spark like windborne embers, and only Alrund can capture them
For three mana, Cap will unattach (i.e., unequip) a piece of equipment he has, dealing the mana value of said gear divided among one, two, or three targets
With something like an evasive Commander with red, you could easily turn your random Treasures from your ramping or mana rocks into a win con in one Commander Damage kill smash