There's a big gap for me between "Favorite" and "That I think are the best".
I love
Word of Command. If it weren't so dang expensive I'd slot it into every EDH deck with
. Its rules text is an abomination, but the idea is beautifully clean. "Make target player cast a spell the way you want." I badly want a revised version with Split Second (Ditto
Piracy on that, but Piracy is a little interesting to me.)
I also really like
Land Equilibrium (though it should be white),
Mana Vortex (would probably be red/black these days), and
Stasis (Fine in blue). Their partners in crime like
Winter Orb and
Smokestack are also up my alley. Don't get me wrong, they're absolutely misery-inducing effects, but they all have a good deal of core charm. I'm glad they exist, both because they're easy to understand and because their existence helps shift the focus of the game away from just being about creatures in combat. They make the game about everything, since when lands aren't as assured you have to balance the value of a card in hand versus a card in the field a lot more carefully, since there's no guarantee your position will get better rather than worse if you wait.