Oh boy, this is tricky. I'm going to take a shot here. I have no idea about the origins, cultural or societal implications that could be inferred from the mask types or if they're even relevant.
Also Spoilers - be warned!
First the basics:
There are 14 different masks in total thus far.
If there is intent in the size, appearance, placement and proximity of masks to another that could form a good basis to speculate. I think that's practically confirmed when you look at the creme and dark ones and relate it to the actions of Dominique and Juliet within the respective episodes; notably the team-up.
Speculatations are roughly listed in order of descending confidence:
- The pink mask, first introduced in ep 3, is Olivia as has been given by Tess. I think the butterflies are noteworthy since we see another mask with the same motif.
- The double mask, first introduced in ep 3, is Kane as stated by Tess. I'm torn why it is a double - either to signify two sides (his dom vs. sub paths or his two origins) or the mask stands in for both Kane and Seth (which I find less likely).
- The creme mask always close to the black mask, both first introduced in ep 3, are Juliet and Dominique respectively. I go by the color to match their hairs, Dominique seems to favor darker outfits and Juliet lighter ones, but they could be the other way round. Doesn't really matter. The aforementioned events of the team-up and how those are reflected in the ep 5 title card strongly hint to the two.
- The red white rose mask, practically the symbol of the game, is either Grym Gudinna or the Gambit Queen. That's mostly based on the prevalance, size and thus importance placed upon it. Notice how the mask is layered behind Olivia's in the ep 6 title card which suggests to me that person will directly steer, support or secretly act through Olivia in the upcoming episode. I favor the idea that the mask is Grym Gudinna based on an end card of ep 1 that has "Grym Gudinna" written and surrounded by the mask and a heart in the thank you message.
- Whichever pseudonym applies: I also suggest that it is Callista based on three points. Firstly the sheer size of the mask goes well with the importance of Callista as the central figure (the protagonists mother, Olivia's teacher, Karlsson's true desire and central mystery figure with a dark past). Secondly the white rose as a symbol of purity, innocence (not as strong as a white lilium but still prevalent) that fits her description as the one "good" person in the company. Thirdly the ep 6 and its position directly behind Olivia which might imply her motherly influence in shaping Olivia to be the crafty politician she is today.
- The half mask, butterfly mask and feathered mask are all new to the ep 6 intro so given the other preview images I suspect at least one of those to belong to some DeKock member, one to a VIP and another that could go to either. There's also a slight chance the butterfly mask and Olivia's butterflies share some connection.
- The golden, ornate mask first introduced in ep 3 is always seen close to Olivia from ep 4 onwards. I have to fit Elena somewhere, so I suggest this represents her.
Now it gets really tricky.
- The jester mask, first seen in ep 3, could be either Veronica or Alessandra. Its distance to every other actor across the episodes is noteworthy. Also the mask appearing in the eye of the red white rose mask is striking. Following my thoughts on the red white rose mask being Callista and recalling the conversation on the boat in ep 5 this mask could only be Veronica's.
- The porcelain, asian looking mask, first introduced in ep 3, is probably Kiyomi. But that's only weakly based on the asian vibe I'm getting from the mask and the scept like handle coming from its chin. Kiyomi is the "muscle"; your capable right hand woman you direct like a scept towards the problem you want to have fixed.
- The flamboyant, red rosed, hatted mask, first seen in ep 3, is always in close proximity of the asian looking mask. Since I've given that one to Kiyomi, this mask could be either Kazumi or Delilah. I'm undecided but give a slight edge to it being Delilah simply because her lore so far seems to hold more potential for further backstory and intrigue with the DeKocks.
- The shrouded, golden mask, first introduced in ep 2 and curiously missing in ep 3, could be either Veronica or Alessandra. I give this one to Alessandra by process of elimination.
- The blood crying mask could be Nathan based on the ep 1 ending cards. Nathan gets a specific mask to his quote while the previous slaves get the same generic variant. However, the mask holds more relevance as it is one of only three masks to appear in episode 2 alongside the shrouded, golden and red white rose mask.
P.S. If you're correct
Vlahurg1 and the blood crying mask is indeed Seth my predictions in the lower list no longer make sense. Also; if that's true we can expect Seth to take on a much bigger role in the future.