There are several canon extinct houses of Dorne, the ruins of which might be built together as a Megabuild, or split off separately as full projects or Mini Builds.
These houses were among the dozen First Men houses of the Greenblood who chose a High King of Dorne from among their number. Three of the houses (unspecified) were destroyed after a generation of warfare following a disputed election. The remaining houses were conquered during the Andal invasion.
They are:
House Lake
House Briar
House Brook
House Brownhill
House Holt - Possibly related to House Holt of the North, their former seat might have been Hellholt.
House Hull
House Wade
House Shell - Possibly related to House Shell of the Vale