I would say Madison stands out on this list since the others listed are all already in very liberal regions. Also Madison literally has no remotely Conservative suburbs while Boston and Seattle have a few.
Which Boston and Seattle suburbs stand out to you as being conservative?
In Seattle, you have a decent handful of Conservative suburbs to the south and southwest of the city; mainly is Pierce County.
In Boston, it's to the immediate north and south of the city core.
Hmm, the further-out South King County suburbs and exurbs don't seem particularly right-wing to me. They vote the way you'd expect relatively blue-collar and Posturbia (working to lower-middle class) suburbs would. You can make an argument for Tacoma's suburbs like Puyallup based on some of them not being clearly D-leaning in recent presidential election results, but it feels weird to think of the Everett and Tacoma suburbs as suburbs of Seattle.
How do you determine which suburbs are more "right-wing"? This certainly doesn't seem borne out by 2020-PRES results in the case of Metro Boston.
