There are a few options for a heat pump dryer in the US, either as a dedicated dryer or as an all-in-one unit that does both the wash and dry in a single drum. Most of the dedicated dryers sold here are 240 volt units as I suspect the manufacturers are expecting you to use them as a direct replacement for a traditional resistive heater electric dryer. The combo machines tend to be 120 volt, though.

The ones I can think of off the top of my head are:

• LG DLHC5502B/V/W - Dedicated dryer, full size, same size as LG's normal front loaders and can be stacked with the WM5500* if you so desire. 240 volt.
• Whirlpool WHD862CHC - Dedicated dryer, full size, can be stacked with the WFW862CHC. 240 volt.
• Whirlpool WHD560CHW - Dedicated dryer, full size, can be stacked with the WFW560CHW and is also the least expensive full size heat pump dryer on the US market as far as I know. 240 volt.
• GE (Profile) PFQ97HSPVDS - All in one, physically larger than a typical US sized machine, seems to get decent customer feedback. 120 volt.
• LG WM6998HVA - All in one, same size as LG's normal front load machines (27x39x33.25"-ish), probably what I'd go for if it were me and I wanted an all-in-one. 120 volt.
• Whirlpool WFC682CLW - All in one, similar in size to a normal 27" front load machine also. Consumers seem to hate the "intuitive" Whirlpool control panel that does not feature a cycle knob. 120 volt.
• Samsung WD53DBA900HZ - All in one, taller than a typical machine but still 27" wide, looks extremely doofy, and Samsung's quality is crap. I would not buy this. 120 volt.

There are also compact variants at a "Euro" sized 24" Wide.

• LG DLHC1455W - Dedicated dryer, 240 volt
• Summit LD2444 - Dedicated dryer, 240 volt
• Samsung DV25B6900HW - Dedicated dryer, 120 volt
• GE GFQ14ESSNWW - All in One, 120 volt
• LG WM3555HVA/HWA - All In One, 120 volt
• LG Signature LUWM101HWA - All In One, 120 volt
• Summit SPWD2203P/W - All In One, 120 volt, I have received poor feedback about this model re: reliability

And of course the European brands pretty much exclusively make 24" compact heat pump dryers, most of which are also ventless: Bosch, Miele, Asko, etc. The Miele machines are 120 volts, the Bosch and Asko are 240.