For what it's worth, I believe these are the only empty buildings downtown that have no announced plans. We'll say downtown is the area surrounded by the river, I-375, I-75 and M10. All of these are 100% unused. I may be missing a few, but these are, at least, the larger ones.
1.
Fowler Building, 8 floors
2.
Film Exchange Building, 7 floors
3.
27-31 State St., 6 floors
4.
1133 Griswold St, 6 floors
5.
Blenheim Building, 4 floors
6.
Moose Lodge, 3 floors
There's a few empty buildings awaiting renovation, awaiting demolition for new construction, and a few with no announced plans but are in the hands of dependable developers. There's also the vacant Executive Plaza on the border of downtown and Corktown, but it's just outside of the 75/375/M10/river area.
Regardless, its a very small number compared to the amount of empty stuff we had 5-10 years ago.