There will be a bonus sheet, called the Mystical Archive cards.
The rarity breakdown for this slot will be:
25 Uncommons
25 Rares
15 Mythical Rares
1 card from this sheet will appear in every Play Booster.
In Japanese-language Play Boosters, the Mystical Archive card will be replaced by a Japanese Mystical Archive card that only appears in Collector Boosters in non-Japanese languages. I’ll post the full breakdown of this below.
These printings will not change the legality of the cards included, except they will be legal to play in Limited.
There will be 10 Special Guest cards in this set as well, appearing in ≈1.82% of packs.
On Arena only, Library of Leng will not appear as a Special Guest in draft, sealed, or in store packs. Library of Alexandria will replace this card as a Special Guest.
The Play Booster breakdown by rarity is:
81 Commons
100 Uncommons
60 Rares
20 Mythic Rares
15 Lands
Five of these will be L rarity dual lands, and are expected to match the 5 color pairs of the schools in this set.
The most common SOS Play Booster pack will have the following rarity breakdown
7 or 8 Commons*
3 or 4 Uncommons*
The non-foil wildcard rarity slot is exactly as likely to be a Common as an Uncommon
1 Uncommon Mystical Archive Card
1 Rare or Mythic Rare
1 Land that is as likely to be a Basic Land as it is to be a Common Dual Land
The Marc Anderson Breakdown:
This is the number of copies of any specific card you can expect to see in an 8-person draft pod, broken out by rarity as follows:
You will see ≈2.05 copies of any given Common
You will see ≈.85 copies of any given Uncommon
You will see ≈.45 copies of any given Rare
You will see ≈.21 copies of any given Mythic Rare
You will see ≈.04 copies of any given Special Guest
You will see ≈.87 copies of any given Uncommon Mystical Archive card
You will see ≈.10 copies of any given Rare Mystical Archive card
You will see ≈.06 copies of any given Mythic Rare Mystical Archive card
You will see ≈2.4 copies of any given Dual Land
Prerelease Packs will contain the following:
5 SOS Play Boosters
1 SOS college-themed booster that will only contain cards from the colleges two colors
For example, the Silverquill pack will only contain White and/or Black cards
1 Traditional Foil card.
1 Deck Box
1 Spindown die that matches the Prerelease Packs’ college
Play Booster Slot Breakdown
Note: I believe there is an error in the Source article I linked above. It lists the number of Common slots as “6-7”, but I believe they forgot to account for the Mystical Archive slot taking up one of the Common slots, and should read “5-6”.
Slots 1 – 5: Always a Common
Slot 6: ≈98.18% of the time a Common
A card Special Guest will appear in this slot ≈1.82% of the time.
Slots 7 – 9: Always an Uncommon
Slot 10: Always a non-Foil card, broken out by the following rarity:
≈39.1% of the time a Common
≈39.1% of the time an Uncommon
≈19.5% of the time a Rare
≈1.9% of the time a Mythic Rare
<1% of the time a Mythic Rare borderless Elder Dragon, planeswalker, or Dual land
<1% of the time a Rare or Mythic Rare field notes card
Slot 11: Always a Rare or Mythic Rare, broken out as follows:
≈82.5% of the time a normal art Rare
≈14.1% of the time a normal art Mythic Rare
≈1.6% of the time a Mythic Rare borderless Elder Dragon, planeswalker, or Dual land
≈1.2% of the time a field notes Rare
<1% of the time a field notes Mythic Rare
Slot 12: Always a card from the Mystical Archive Bonus Sheet, broken out by the following rarity
≈87.5% of the time an Uncommon
≈9.6% of the time a Rare
≈2.9% of the time a Mythic Rare
Slot 12 (Japanese language Play Boosters only): Always a card from the Mystical Archive Bonus Sheet, broken out by the following rarity:
≈58.3% of the time an Uncommon
≈6.5% of the time a Rare
≈2% of the time a Mythic Rare
≈29.1% of the time an Uncommon Japanese Mystical Archive card
≈3.2% of the time a Rare Japanese Mystical Archive card
<1% of the time a Mythic Rare Japanese Mystical Archive card
Slot 13: Always a foil card, broken out by the following rarity:
≈54.4% of the time a Common
≈33.6% of the time an Uncommon
≈6.7% of the time a Rare
≈1.1% of the time a Mythic Rare
<1% of the time a Mythic Rare borderless Elder Dragon, planeswalker, or Dual land
<1% of the time a Rare or Mythic Rare field notes card
≈2.8% of the time an Uncommon Mystical Archive card
<1% of the time a Rare or Mythic Rare Mystical Archive card
Slot 14: Always a Land, broken out as follows
≈26.7% of the time a non-foil normal art Basic Land
≈6.7% of the time a foil normal art Basic Land
≈13.3% of the time a full art Basic Land
≈3.3% of the time a full art foil Basic Land
≈40% of the time a Common Dual Land from one of the 5 schools
≈10% of the time a foil Common Dual Land from one of the 5 schools
Note that there are only 5 Common dual lands that appear in this set.
Slot 15: Always a double-sided token or a Non-foil punch-out counter card
