I'd say my 3 favorite cards that I've always tried to work into decks are,
Goblin Sharpshooter: By far my favorite Goblin. any one toughness creature is
dead, and anytime you sacrifice one of your own creatures (pretty often with goblins) you get to ping your opponent. And in multiples they really go crazy. With a free sac outlet like
Goblin Sledder, you can do 10-20 damage with a couple of these guys. Love working them in. Wish they were modern legal.
Mistbind Clique: Such a crazy card. Easily the biggest faerie and the one most responsible for wins. Plus, nothing is better than a denied
Path to Exile because of a Mistbind trigger. Such a fun card to play with.
Worship: strange card, because it fits in controlly decks, but is best suited to aggro with lots of creatures. In something like Naya Zoo, your opponent never sees
worship coming and typically struggles to play around it. Just a fun card that gives a deck more options than it has any business having in the first place.