Out of date information ahead.
King County Metro keeps an up-to-date PDF collection of schedules from the last public shakeup. This page is meant for bus fans, like me, to indulge in out-of-date information about old bus routes. Remember, this stuff is out-of-date. I have said that much. For the latest shakeup, see King County Metro. For the current state of transit, including specific information about service disruptions, events, and construction re-routes, please subscribe to Transit Alerts. For information about changes during past shakeups, please refer to their archives. For all other transit agencies in the central Puget Sound region, see here.
One post on Northwest Bus Fans reminded me about how much I loved to keep old timetables as a kid. Before I had the technology, it was quite impossible for me to keep every route number and every schedule that was on the racks.
King County Metro (all-county by shakeup)
2018 March — https://1drv.ms/u/s!AmzcIMaZAenXjOB_3ONHsSuf4yvMDg
2017 September — https://1drv.ms/u/s!AmzcIMaZAenXjNE7jJdWXhoyuCrqTw
2017 March — https://1drv.ms/u/s!AmzcIMaZAenXjK4MeJVDQe7og6qhYg
2016 September — https://1drv.ms/u/s!AmzcIMaZAenXjKJ6C_ttbjFEExB8Jg
2016 March — https://1drv.ms/u/s!AmzcIMaZAenXjJFG9L0QMUmzDBty3w
2015 September — https://1drv.ms/u/s!AmzcIMaZAenXi9Upc33Eq0J6kB0ZYQ
2015 June — https://1drv.ms/u/s!AmzcIMaZAenXi9Uqd6OXP5gppgyt2w