Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Birds of Paradise

Counter target spell unless its controller pays {1}.

{T}, Sacrifice a creature: Blasting Station deals 1 damage to any target.
Whenever a creature enters, you may untap Blasting Station.

Search your library for a creature card, reveal it, then shuffle and put the card on top.

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

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

Reach
When Arboreal Grazer enters, you may put a land card from your hand onto the battlefield tapped.

Search your library for up to two creature cards with different names, reveal them, put them into your hand, then shuffle.

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Defender
{T}: Creatures you control gain haste until end of turn.

Whenever another creature enters, untap Midnight Guard.

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Enchant creature
Enchanted creature has "{T}: Create a 1/1 green Elf Warrior creature token."

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

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.