The assets are tested in Unreal Engine, and I'm not sure how good they work in other platforms. But when importing them in Unreal the outline becomes white, you just need to modify the material color to black(or whatever color you want).
The bundle has 4 big signs and 8 smaller ones, with the option of having txt or not(just switch from the normal texture to the blank one). The free one has 2 big signs and 2 small.
I am still learning how to make assets so if there are any problems with them please let me know and I will try to fix it.