Washburn

Washburn originally was the Lyon & Healy premium brand, then owned by Tonk Bros, then Regal and then Harmony). I don't know when it was acquired by USM but they have resurrected it and mainly seem to use it for Guitars. There are some more recent Ukuleles that are branded Washburn though, like the Disney "High School Musical by Washburn Ukulele and the Koa Laminate concert Ukulele with GWL on the headstock sold as by George Washburn Lyon Ltd., this was done as a special order brand for K-Mart, Sears and Wal-Mart, the US retail giants. They did the same thing but branded the Ukuleles Lyon by Washburn for Costco. 

I have also seen some Washburn branded ukuleles that look very similar to an Oscar Schmidt ukulele on sale in Europe, (where they don't sell Oscar Schmidt?).

Vinci

This has been USM's range of strings with publicity claiming the brand was founded in 1953 and invented mechanically wounds strings; Maybe? 

In 2012 they branded a small range of laminate Ukuleles, these were made in China and possibly aimed at the lower end of the market so Oscar Schmidt could go more upmarket? (this range seems to have disappeared by 2014 shortly after USM started to do some of the more Washburn orientated branding - same plan different names?)

Jay Turser

This one is not a historical name resurrected, Jay Turser was founded in 1988 and is a range of Guitars and Bluegrass instruments branded by U.S. Music Co. In their catalogue there is currently a Banjolele, (score one more for the Dae Won Dub2R).

Kai

In 2013 USM introduced a small selection of colourful budget Sopranos with the branding Kai on the headstock. These are made in China and it say USM on the sound hole label. Everywhere I have seen them for sale the reseller says they are part of the Oscar Schmidt range but they aren't, they are just another US Music brand?

Others

Going back to acquiring famous old brands though, USM also currently own the Framus brand name, the Hagstrom brand name, the Warwick brand name, the Marshall brand name and some others too? These though, they don't use on any Ukuleles and its all a little murky as to what they own and what they are just US distributors for?

KMC Music

Another US distribution firm JAM has taken over is KMC Music which amongst other things brought with it whatever remains of the old New York distributor C. Bruno & Son. I don't think they use any of these names though but they do have a few Ukulele brands of their own. These brands include Jasmine and Sierra, and possibly others as they own a number of other Guitar brands Including Hamar, (and one called Amigo; I have seen budget Amigo sopranos but I don't know if they are part of this range?) From the look of it, overall KMC is a bit lower budget that a lot of what USM do?

Coast Music

In Canada JAM Industries have another distribution subsidiary called Coast Music and this arm, as well as being the Canadian distributor for some major music brands, (and the USM brands), has its own house brands too, including Alabama a range of folk instrument that does not include Ukuleles or Guitars but does include Banjos, and in the Banjo range there are a couple of re-branded Dae Won DUB Banjoleles.