Color identity is of course of great relevance to the Commander format, where youre limited only to cards with a color identity that matches your commanders
Until the end of your next turn, you may play those cards
Appearing in Into the Inklands selection of emerald cards, Ursula, Deceiver of All costs three mana to play - or can alternatively be added to your inkwell - in return for two strength, three willpower and a single point of lore
I normally dont care much for generic good-stuff commanders in three or more colors, but this one feels great
Dont forget about those changelings either
Sylvan Library is a classic repeatable card draw engine, and can net you an extra two cards per turn (provided you have the life to pay for it)