Elven Riders

Elven Riders can't be blocked except by Walls and/or creatures with flying.

Ashnod's Coupon

{T}, Sacrifice Ashnod's Coupon: Target player gets you target drink. You pay any costs for the drink.

Goblin Welder

{T}: Choose target artifact a player controls and target artifact card in that player's graveyard. If both targets are still legal as this ability resolves, that player simultaneously sacrifices the artifact and returns the artifact card to the battlefield.

City of Solitude

Players can cast spells and activate abilities only during their own turns.

Phelddagrif

{G}: Phelddagrif gains trample until end of turn. Target opponent creates a 1/1 green Hippo creature token.
{W}: Phelddagrif gains flying until end of turn. Target opponent gains 2 life.
{U}: Return Phelddagrif to its owner's hand. Target opponent may draw a card.

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Goblin Recruiter

When Goblin Recruiter enters, search your library for any number of Goblin cards, reveal them, then shuffle and put those cards on top in any order.

Cathedral of Serra

White legendary creatures you control have "bands with other legendary creatures." (Any legendary creatures can attack in a band as long as at least one has "bands with other legendary creatures." Bands are blocked as a group. If at least two legendary creatures you control, one of which has "bands with other legendary creatures," are blocking or being blocked by the same creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Undiscovered Paradise

{T}: Add one mana of any color. During your next untap step, as you untap your permanents, return Undiscovered Paradise to its owner's hand.

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.