Add NED 1m data, where available.

[zerebubuth]

From the USGS NED site:

1-meter – This dataset was introduced in 2015 with limited coverage of the U.S., but will be expanding as new DEMs from 3DEP quality level 2 or better lidar data are acquired. Horizontal coordinates are referenced to the Universal Transverse Mercator projection.

Note the different projection.