mtg commander precon 2017 POV: it is & you are invited to play the new decks in a 4 player pod and interesting Commander Series: List of Commander

Seedborn Muse is a very powerful card, so any card that has a similar effect is likely to be very powerful, as well, even if it works only for a specific group of cards, as is the case with Murkfiend Liege, which balances its ability being more specific by making creatures more powerful

Basically any buyback spell is, but this and Wurmcalling are basically the two rares worth it

The giant wept tears of embers for the deaths of his allies. Azeworai, The Lonely Giant Illustrated by Rogrio Vilela Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Legal Comp

Projektor Inspector also has nice synergy with it