What's in a booster?

Weiss Schwarz has very specific structure to its booster packs, and a booster box contains reliable patterns (unlike some TCGs that have very random boosters). I've gathered those patterns here.

Each booster pack (except in Extra sets; more on that later) has 8 cards:

• 1 Climax
• 1 in 5 packs will have a Climax Rare
• A booster box (20 packs) will always have 1 of each of the 4 Climax Rares in that set.
• 4 out of 5 will have a Climax Common
• A booster box will always have 2 of each of the 8 Climax Commons in that set.
• 1 Rare or higher
• SP – Special – A signed foil, or in older sets, a foil Climax.
• 1 in 160 packs. A carton of 16 boxes will always have 2.
• RRR – Triple Rare – A foil rare, often with alternate art.
• 1 in 80. A carton will always have 4.
• SR – Special Rare – A foil rare, with normal art.
• 1 in 32. A carton will have 10, and each box will have 1 of SR, SP, or RRR
• RR – Double Rare – A foil card, different than cards than Rares.
• 1 in 5. A booster box will always have 4: 1 of each color.
• R – Rare
• 3 out of 4 packs will have a regular rare. A box will have 15 different rares.
• *Note that some sets are a bit different, since some don’t have any of certain rarities.
• 2 Uncommons
• 4 Commons 

Normal sets are 80-100 cards, and opening 4 or 5 boxes usually gets you a playset (4 copies of each card) of the whole set, except for alternate art cards.

Extra Boosters have only 6 cards, and cost a bit more, since they always have foils:

• 2 foils (just foil versions of the normal cards)
• Either 1 Rare and 1 Common or 2 Commons
• 1 non-foil Rare
• 4 or 5 non-foil Commons.
• There are no SP, RRR, SR, or RR cards in Extra Sets

Extra Boosters come in 6 pack boxes, and Extra sets are only 36 cards. Opening 5 or 6 boxes usually will get you a playset of the whole set.

Any pack will never have 2 copies of the same card.

Sources: 1.  2.  3.