Elesh Norn, Grand Cenobite

Vigilance
Other creatures you control get +2/+2.
Creatures your opponents control get -2/-2.

Kormus Bell

All Swamps are 1/1 black creatures that are still lands.

Drana and Linvala

Flying, vigilance
Activated abilities of creatures your opponents control can't be activated.
Drana and Linvala has all activated abilities of all creatures your opponents control. You may spend mana as though it were mana of any color to activate those abilities.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.