These are a really excellent start, and I think that they represent the era perfectly.If you could tell us which factions each icon represents then that would be awesome.

As for some feedback: the most pressing matter is that the second, third and last icons seriously need a contrast buff; at the moment it is nearly impossible to distinguish the actual sigils from their backgrounds.

Otherwise, things look fine: you have generally chosen good colour combinations, and the icons have just enough detail to be interesting without becoming visually noisy.However, improving these will all really depend on what you‘re going for as an end result: do you want these to be in the same sort of flat colour style as they are now, or do you want to flesh them out and give them some depth?