- Elesh Norn, Grand Cenobite: The white Praetor and /tg/'s eldritch Phyrexian waifu. You probably came here from her page. Leader of the Machine Orthodoxy, which is essentially the bastard Phyrexian child of the Ecclesiarchy (or possibly the Inquisition). According to Elspeth Tirel in pre-Theros fluff, she is currently kicking the shit out of the other Praetors; so far, Sheoldred and Urabrask have been confirmed to have been thrown under the Norntrain.
- Jin-Gitaxias, Core Augur: The Blue Praetor. Leader of the Progress Engine, the faction religiously obsessed with machines, knowledge, and "progress".
- Sheoldred, Whispering One: The Black Praetor. Leader of the Seven Steel Thanes, and runs her faction as a callback to vintage Phyrexia. Kicked all sorts of Mirran ass, including (presumably) taking out Koth. Along with Urabrask, she has been confirmed to have been conquered by Elesh Norn.
- Urabrask the Hidden: The Red Praetor. In charge of New Phyrexia's industry. He also sheltered the shattered remnants of the Mirran resistance, because exposure to red mana makes you a total bro in Phyrexia. With a CMC of five, he is the closest thing to playable that the Praetors get outside of EDH. Unfortunately for him (and the Mirrans), viability in Constructed is of no concern to Elesh Norn.
- Vorinclex, Voice of Hunger: OM NOM NOM NOM NOM NOM NOM NOM NOM NOM NOM NOM.
Crunch-wise, they all give their controller some useful effect and their controller's opponents something vaguely the opposite of that effect. In addition each has a evergreen keyword ability associated with its color (except Urabrask, sorta). However, their ridiculously high mana costs tend to make them unplayable in anything other than EDH. All of them are legendary creatures (which of course fluff wise says they are 1 of a kind).
There are two other creature cards with the "Praetor" type in MTG, but nobody really cares about those guys.