Yes, the judicial positions in WA state are non-partisan, both at the state and local levels, as are school boards and, at least in Seattle, the mayor and city council (those are off-year elections and so we didn't vote for them this time; they will be ranked choice in 2027). You can't vote a straight party ticket anyway, nor is party registration really a thing here. Almost all of that dates back to the Progressive movement at the turn of the previous century when many Western states wanted to get corrupt party politics out of, well, politics. (King County, which Seattle is a part of, switched to non-partisan offices a couple of decades ago when it became clear to the GOP that even in the suburbs they were becoming unpopular and wanted to hide who they were; it didn't really work for them.) Statewide positions and the Lege are partisan and in other counties/cities they may be as well.
For the non-partisan positions I do study the state and county voters' guides as well as other sources - sometimes the candidate's statements in the guides are clear evidence; sometimes it's who they claim support from. There have at times been efforts by the right to "flood the zone" particularly when it comes to the state Supreme Court; to my relief the voters have seen through that to date. This year that didn't happen. We'll see what the voters think about the efforts via initiative to overturn some of the more progressive recent legislation to come out of Olympia.