Upon the merger of Alaska and Virgin Airlines in 2016, a special merger livery was applied to select aircraft. Featuring a five color gradient paint scheme, it still is striking years later. The paint was tinted with mica adding a sparkle effect to the livery. (Not currently featured due to paint kit limitations.) The livery is painted on a Boeing 737-900ER as well as a few A321's and some liberty was taken to apply it the -800 here. This rendition features the current look on the -900ER which removes the Virgin text and adds a Oneworld sticker next to the door. There may be future options to re-add this missing text in the future.
Update 2/11/2023: You can find the 900ER version that this livery is one in real life here: https://flightsim.to/file/49918/alaska-airlines-pmdg-boeing-737-900er-more-to-love