The Dragonlord Silumgar has seen play in Standard, Modern, and EDH.
This Elder Dragon is pretty good. He's a great target for Sultai reanimator decks to bring back from the graveyard. While he doesn't have the raw power of many of the other Dragons in the set, the deathtouch and ability to steal an opponent's strongest threat makes him very powerful.
Silumgar can also serve as a decent blue/black Commander of a deck built for control. He's also used as a complementary piece in the EDH format, however, especially in Scion of the Ur-Dragon and Marchesa, the Black Rose. His previous form in Fate Reforged, as Silumgar, the Drifting Death, is also a good choice for Commander. The older form being a 3/7 with Hexproof makes it harder to deal with, plus having the ability to make your opponents' defending creatures lose -1/-1 each time a Dragon attacks is easier to build around. But the Sower-type ability is very powerful and the Dragonlord has become considerably more popular as a Commander.
In any case, Dragonlord Silumgar was a great card in a highly Dragon-friendly Standard format and has even seen competitive Modern play. Beyond that, he should continue to be a casual favorite with strong playability in both control decks and Dragon-themed decks.