The Laney College Carpentry Department in Oakland, California built a net zero tiny house, the Wedge, in 2016 for the SMUD Net Zero Tiny House Competition
That tiny house is for sale for
Laney College carpenters are currently building two other prototypes tiny houses, the Pocket House, for the unhoused and homeless in Oakland
The Northern Nomad is another net zero tiny home designed and built by a group of students from Carleton University in Canada as this video from 2019 shows:
Northern Nomad Tiny House
Reading Design Guidelines for a Net Zero Tiny House (https://tinyhousedesign.com/design-guidelines-for-a-net-zero-tiny-house/) and Guide to Off-Grid Tiny Houses (https://gosun.co/blogs/news/guide-to-an-off-grid-tiny-house), the core idea seems to be energy efficiency first, last, and always: the less energy you use the easier it becomes to supply it with renewables onsite.
That core idea of energy efficiency applies to all houses, not just tiny houses.