I live in the puget sound region and I enjoy listening to air traffic control communications. LiveATC has been very helpful for listening to air traffic control in the area, since I get poor reception of even aircraft. The Seatac feeds that were added in late 2020 significantly improved coverage for the airport and the seattle TRACON. However, these feeds could have some improvements over what they currently are. The clearance frequency has been missing since the feeds were first added, and the final approach frequency (my personal favorite) has been missing for around a year. the Seatac feeds have relatively poor reception, and can't receive transmissions from aircraft not close and in view of the receiver. The receiver seems to be on the west side of the airport, so the ramp control can only be barely picked up.
There are less feeds in the area than there were when the seatac feeds were added. the single frequency feeds for boeing field (BFI) have been removed a while ago leaving just a combined feed (which has only been receiving the tower frequency lately) and the feeds for Paine Field (PAE) and Thun Field (PLU) have recently been removed.
If you lives near an airport in the area or know someone who can upload a feed, I have attached a word document with a list of tower, tracon, and center frequencies in the puget sound area and their sectors and transmitter locations. (which would be a great resource on its own.)