immunology - What cells would have the CD3 marker on them (other than T-cells)

As you know CD3 is

a protein complex and is composed of four distinct chains. In mammals, the complex contains a CD3γ chain, a CD3δ chain, and two CD3ε chains.

Natural Killer (NK) cells have been shown to express CD3 epsilon proteins, but not CD3 delta or gamma.

Also on a side note, there are several other non peripheral mononucleated cells besides Purkinje cells that can express CD3, but mostly in pathological circumstances. For instance Warthin-Finkeldey cells, also known as polykaryocyes, display CD3, although the origin of these cells is not certain (they might be multinucleated T-cells).

(PS: If you want more information on CD3, I found this site very interesting.)