Obzedat, Ghost Council and Blood Baron of Vizkopa are good, but they do not trump Whip of Erebos in any racing situation
It sells for ungodly amounts of money
Regidrago can be powered up in just two turns (Double Dragon Energy and a basic Grass energy), and from that moment on, the possibilities are endless: you can either lock your opponent with Noivern, wipe the entire field with Kyurem, or gain extra turns with Dialga (yes, you read that right)
If you do, change "target" in its text to "each.") Sorcery Innkeeper's Talent (Gain the next level as a sorcery to add its ability.) At the beginning of combat on your turn, put a +1/+1 counter on target creature you control
They essentially give you access to Past in Flames from the command zone, which is extremely powerful by itself
Im sure you already know that drawing cards is one of the most powerful things you can do in the game