A recent post on the RA Facebook page asked about the Ideal Laundry building that used to be at 506 Soquel Avenue (between Ocean and Ocean View). That building, built in the 'Streamline Moderne' style popular here in the late 1930s, has been replaced by apartments, but a number of similar small commercial buildings remain in this section of Soquel Ave, and also over on Water Street.
Next door to the former Ideal Laundry location, at 510 Soquel, is an example of the slightly older neo-classical revival style, with square, fluted pilasters imitating Greek columns. The 'Moderne' movie-theater-style marquee over the entry, perhaps inspired by the 1936 Del Mar Theater, gives the building an eclectic feel. The building has been home to Woodstove & Sun for many years. To the right, part of the apartment complex that replaced Ideal Laundry can be seen.
Up the street at 536 Soquel is a tiny, cute building with prominent rounded corner columns. Such rounded elements are characteristic of the Streamline Moderne (note also the planting beds). A large fabric awning obscures the original above-window treatment.
Yet another nicely preserved/restored/imitative example of the Moderne style can be found at 1315 Water Street. the rounded elements are there, along with flat, projecting hoods over doors/windows - another common Moderne characteristic. The steel-frame windows were also common in this period.
I haven't checked the age on any of these buildings, or looked for old photos, so can't say which features are original.
As always, The Sidewalk Companion to Santa Cruz Architecture is the place to look for other examples of this style in downtown Santa Cruz. Check out the Alsberge building (p.64) at the Church-Chestnut corner, and the 'Judah House' (p.12) on Third Street.