This page contains torrents for 100% free and public domain raster maps for unlocked Garmin devices. The files are distributed via http-seeded torrent. I recommend you download the maps with qBittorrent.
See this post for instructions how to install these maps and others.
USGS National Map
I produced these maps from USGS National Map Data. The two types of maps are ImageryOnly (aka Satellite) and Topographical.
These maps were produced late 2019.
|Arizona ImageryOnly||29 GiB|
|Arizona Topo||16 GiB|
|Colorado ImageryOnly||26 GiB|
|Colorado Topo||17 GiB|
|New Mexico ImageryOnly||24 GiB|
|New Mexico Topo||15 GiB|
|California Topo||(Coming Soon)|