Smoldering Marsh [The Lord of the Rings: Tales of Middle-Earth Commander]Set: The Lord of the Rings: Tales of Middle Earth Commander Type: Land Swamp Mountain Rarity: Rare (T: Add B or R.) Smoldering Marsh enters the battlefield tapped unless you control two or more basic lands. Before the shadows of evening were long in happier lands, they went on again with only brief halts until they had come to the very midst of the Dead Marshes.

Put two of them into your hand and the rest into your discard pile

Set: Magic Premiere Shop 2007 Type: Basic Land — Swamp Rarity: Common ({T}: Add {B}

Set: Innistrad: Midnight Hunt Type: Creature — Horror Rarity: Rare Cost: {3}{U}{U} Whenever Sludge Monster enters the battlefield or attacks

If a permanent entering the battlefield causes a triggered ability of a permanent you control to trigger

Set: Future Sight Type: Artifact — Fortification Rarity: Rare Cost: {2} Fortified land has indestructible

you may have that player gain control of Slicer until end of turn

Set: Iconic Masters Type: Enchantment Rarity: Uncommon Cost: {3}{W} At the beginning of each end step

then will I give you your true name

Set: Zendikar Rising Prerelease Promos Type: Creature — Elephant Rarity: Rare Cost: {1}{G}{G} Landfall — Whenever a land enters the battlefield under your control

Set: Commander Legends: Battle for Baldur's Gate Type: Land Rarity: Rare Wandering Fumarole enters the battlefield tapped

Shatterskull Pass is a pretty distant second

Set: Commander 2013 Type: Sorcery Rarity: Rare Cost: {2}{W}{W} Destroy all creatures