If the number of historic cards in your graveyard changes while activating mana abilities, the cost to cast The Capitoline Triad remains what you previously determined
While there are some Commander applications with the Avatar Horror, the card is seeing the most play in Standard within Four-Color Zur and Domain Ramp, which uses Zur, Eternal Schemer to give your Overlord cards deathouch, lifelink, and hexproof
5 Tinker Time Tinker Time's main strategy revolves around artifacts
Turning a 5/5 into a 2/2 for just two mana - while providing a bonus to your own strategy - definitely makes for an interesting card
These ten cards all can start the Day/Night cycle and most of them have abilities that will trigger any time it switches between the two
It's not without reason, the Library is restricted in most Old School formats and even banned in others