In some countries you can find a lot of vintage satellite imagery. The EOX one goes back to 2018! But those are not very useful in Every Door, since people should use imagery there only to orient themselves. The freshest one is largely enough for that.
Given HOT publishes OpenStreetMap layers and extracts to HDX, any OSM map is an HDX map.
Every Door is used in humanitarian contexts to map water sources, health facilities etc. There is no specific HDX tagging, and no other database. Although soon there could be, with custom presets and pre-upload hooks.
#30DayMapChallenge