In which cases does the 3d subshell take precedence over the 4s subshell?
If we take the definition of "3d subshell takes precedence over the 4s subshell" as being that the configuration has zero 4s electrons, yet at least one 3d electron, then all such cases are ions.

+1  

V: 3d^4
Cr: 3d^5
Co: 3d^8
Ni: 3d^9
Cu: 3d^10   

2+

All elements from Sc to Zn

3+  

All elements from Ti to Ga

Etc.