To determine that value, look at the nontoken creatures you control and count each one that entered this turn
Sapphire: If you want resources at your disposal, this is the color for you
Evelyn, the Covetous I think that The Beaches pretty much said it all
Chapter III in particular makes attacking feed you cards, so sometimes Shiva plays out like two turns of Moat. You can also try to combine this with other stun effects to draw extra cards, though there arent many of those (mostly just Ice Flan and Omega, Heartless Evolution)
Spectral Adversary Imagine being attacked by a large army only to surprise your opponent by flashing in this blue creature
There are some good options, like Circuit Mender and Solemn Simulacrum, but your go-to big colorless creatures, the Eldrazi, have built-in limitations that make them rubbish for blinking