Errant and Giada

Flash
Flying
You may look at the top card of your library any time.
You may cast spells with flash or flying from the top of your library.

Urabrask the Hidden

Creatures you control have haste.
Creatures your opponents control enter tapped.

Raff Capashen, Ship's Mage

Flash
Flying
You may cast historic spells as though they had flash. (Artifacts, legendaries, and Sagas are historic.)

Mountain

Island

Sonic the Hedgehog

Haste
Gotta Go Fast — Whenever Sonic the Hedgehog attacks, put a +1/+1 counter on each creature you control with flash or haste.
Whenever a creature you control with flash or haste is dealt damage, create a tapped Treasure token.

Mystic Monastery

This land enters tapped.
{T}: Add {U}, {R}, or {W}.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.