In the Standard top 8 decks or sideboards of Pro Tour Theros, there will be at least one copy of: a Theros rare/mythic that I haven't listed in my other predictions (predictionbook.com/predictions/21290 to 21335)

Created by Roxolan on 2013-09-14; known on 2013-10-14; judged right by ygert on 2013-10-13.

Roxolan estimated 22% on 2013-09-14
Roxolan said “Bident of Thassa, Nighthowler, Ashen Rider, Medomai the Ageless, Ember Swallower, Celestial Archon, Labyrinth Champion, Anthousa, Setessan Hero, Polis Crusher, Psychic Intrusion, Underworld Cerberus, Pyxis of Pandemonium, Hundred-Handed One, ” on 2013-09-15
Roxolan said “Meletis Charlatan, Shipbreaker Kraken, Abhorrent Overlord, Hythonia the Cruel, Rageblood Shaman, Titan of Eternal Fire, Triad of Fates, Akroan Horse, Colossus of Akros.” on 2013-09-15
ygert estimated 60% and said “It’s a conjunction, so even with the probability of a given one being low, the overall probability is not.” on 2013-09-17
ygert said “*disjunction” on 2013-09-17
Roxolan said “@ygert So your average probability for a single card in the 22 is something like a 4%? Hmm. Does that mean that you’d tend to rate my 3%/5% cards higher? (predictions/21321 to 21335)” on 2013-09-17
ygert said “Yes, I think so, for some of them at least. I haven’t analyzed each one individually yet, so I haven’t made estimates on the pages of those predictions, but I’ll probably work my way over to them.” on 2013-09-17
ygert said “A note: by the nature of how these things work, I’d assign to a good fraction of the cards this prediction is about a probability of ~0. But others I would give a comparatively higher chance to.” on 2013-09-17
ygert said “I feel that if you really wanted a “all the rest” prediction, there are some that need separating out of this list. I’d, say, give Abhorrent Overlord a 10% (the probability of MBC being a thing),” on 2013-09-17
ygert said “and likewise give higher odds to, say, Polis Crusher.” on 2013-09-17
Roxolan said “Point taken. I don’t really see Abhorrent Overlord (not that I trust my knowledge of Standard much; that’s sort of the point of this exercise), but Polis Crusher did waver in the 3% area for a while as I was building my list.” on 2013-09-17
ygert said “About Abhorrent Overlord: It could see play in Mono Black Control, otherwise, not at all. As I have said earlier, I consider it unlikely but not impossible (10%) that MBC is, in fact, a thing. (See prediction 21365)” on 2013-09-17
ygert judged this prediction right on 2013-10-13.
ygert said “The conjunction strikes: See for instance, the Bident. A priori, maybe it was right not to rate that specific card higher, but between all the cards here, the chances of at least one making it were definitely not low at all.” on 2013-10-13
Roxolan said “Hey, I’ll not call myself underconfident until I’ve checked the result for all my other Pro Tour predictions.” on 2013-10-13
Roxolan said “Two of them ended up being played (Bident of Thassa and Ember Swallower). I greatly underestimated the number of Theros rares that would see play (24/68, expected 10/68) so my baseline probabilities were wrong.” on 2013-10-13
Roxolan said “Expected something like the pre-Theros Standard decks. Was completely blindsided by all the devotion-heavy mono-colored decks. Have learned a valuable lesson.” on 2013-10-13