Tranquil Thicket is at its best in something like Slogurk, the Overslime or The Gitrog Monster (i.e., commanders that care about lands going to the yard), but is hardly limited to those
Mortarion, Daemon Primarch Life loss matters is a difficult thing to manage
While these lands have a relatively high cycling cost (three generic mana), the added flexibility makes them incredibly useful in Standard, Pioneer, and Commander
Slaying Mantis 5GG Creature Insect Wrestler 6/6 Just a second (As long as this spell is on the stack, players can't move cards on the battlefield.) Slaying Mantis enters the battlefield by being thrown from a distance of at least three feet
Whether the new Foundations decks will follow this pattern, or they'll differ from their counterparts from four years ago remains to be seen