Two sets of skin collections are coming right before the 13th CS:GO Valve Major—The Inferno Collection and The Nuke Collection.
Found in a datamine from a recent update, each souvenir package contains a new set of skins that are much different than past collections. The biggest difference between the two is that there will be skins for the new MP5-SD SMG, which was added to the game last month.
The old Inferno Collection, for example, only had six blue skins with gold stickers plastered on them. The new Inferno Collection is apparently going to have 18 skins, but this hasn't been confirmed yet. The same also goes for the Nuke Collection, which had nine skins that varied from light blue all the way up to purple in rarity. The new Nuke Collection will apparently have 18 skins as well.
It's unclear whether these new collections will have skins with golden stickers, especially considering the fact that there are so many skins in each package. Usually packages range from light blue to purple, but the seemingly large amount of skins in both collections suggest that the rarities could range from light blue all the way up to red.
Other souvenir packages, like the Cache, Dust II, Mirage, Overpass, and Train Collections, didn't receive new skins for the upcoming FACEIT London Major. This could still change though, when players figure out which packages have certain skins.
Souvenir packages will start to drop into Twitch-linked Steam inventories when the London Major begins on Sept. 5.