Darkness of Eternity is card disadvantage, but the threats are so good these days that casting one or two turns early is worth being down a card
The original Ugin costs a hefty eight mana, but its one of the best eight mana spells in the game
Hellraiser Goblin 2 If you really need haste then this is an option
And it can get abusive, if you have say a Clock of Omens and a Mana Vault, or an even bigger artifact source, you can probably go infinite with something like this
Masters Of Evil is a Grixis (blue/red/black) deck based on the villains of Doctor Who, containing cards that are solid on their own and as a set
If Machine God's Effigy somehow enters the battlefield at the same time as another creature, it can't become a copy of that creature