These are the ones that i am aware of.
Ancient Sufi shrines Mausoleums and Tombs In Sanaag
Close up of the one in the middle which is Shaykh Samaaroon (Imam Ali Siciid)
Ancient mosque in Maydh Sanag
Ancient coastal mosque in berbera
Ancient Mosque in Berbera, they need to restore this.
It was more intact just a few decades ago
Another ancient mosque in Berbera
Another one.
Sufi shrine and adjacent mosque of of Aw Barkhadle near Hargeisa.
Ancient Mosque between Garowe and Bosaso
I remember seeing another mosque picture floating around attributed to Hafun , haven't really found confirmation on that one.
The rest of the surviving ancient mosques and shrines that are like 300+ years old and so that are not in ruins seem to be concentrated in Harar. But we all know the story there, unfortunately. There might be a few in other places in Ogaden and around Bur/Juba area.
Among the old major coastal towns in the north like Zayla, Hafun, Bosaso, Maydh, and Berbera haven't fared well due to late 1800s and early 1920 bombardment by colonialists from the sea, and in the 1500s and partial abandonement or full abandonment with Zayla due to french railroad system. Same with other smaller settlements.