There are 3 All-State List constructions in Washington State. One is prepared by the Washington State HS Baseball Coaches Association which takes nominations from HS coaches and reviews stats, college commitments etc. I prefer this list because it's literally an All-State Team constructed by Conference Size (4A, 3A, etc). 9 players on the first team and 9 players on the second team. Period. The main downside to their list is that because it's exclusive and somewhat democratic, excellent underclass kids will miss the list if their school has two or three candidates in 12th grade.
A second all state list is prepared by a collaboration of news organizations (I think its the local USA Today and a local TV station) and is highly influenced by appearances in the State final four and statistics reported to Max Preps. They miss some of the State's best players every year whose programs don't make it to the Final Four or whose coaches eschew publishing team stats (Max Preps is utterly unreliable for baseball in Washington). Their system also favors kids who had great moments in the playoffs despite maybe being mediocre overall.
The same news organizations collaborate on a pre-season "who to look for" article which inevitably features kids who played well in the State semi's and finals. Period. The main positive of this All State list is that it is literally an All State list in that players from all five levels of conferences show up on one list. But I personally found the holes in the list incredibly frustrating and lazy, so I prefer the Coaches Assoc list myself.
The 3rd list in Washington is a collaboration of two in-state newspapers. It's the most exclusive, and I think the most prestigious; the Star-Times "players of the year" by sport, by season. The list is usually 6 to 10 players, at most. Each season, the newspapers have big deal photo shoots, and for the most part they get their choices right. This one hurts me personally, because the reporters that prepared the list actually contacted me after my son's best year in HS only to tell me he missed the list by one vote because he was an 11th grader at the time. Ooooh, singed! Haha, I was so triggered I still get anxious thinking about it! Hahaha!