Over the years Dell have produced a few thin clients - some being rebadged versions of non-Dell hardware.
In March 2012 they completed their acquisition of Wyse Technology to gain a significant position in the marketplace. Since then Dell-Wyse have continued to produce thin clients but essential under the Wyse brand though the 'Dell' aspect is discreetly evident on datasheets and the hardware.
I have continued listing these thin clients under the Wyse tab.