Which metals hydroxides dissolve in excess NH4OH?
The Wikipedia article for "Metal amine complex" gives many examples.  According to the article:  


  Almost all metal ions bind ammonia as a ligand, but the most prevalent
  examples of ammine complexes are for Cr(III), Co(III), Ni(II), Cu(II)
  as well as several platinum group metals.


Specific examples include:  

$\ce{[Pt(NH3)4][PtCl4]}$
$\ce{[RhCl(NH3)5]Cl2}$
$\ce{[Cr(NH3)4Cl2]Cl}$
$\ce{[Co(NH3)6]Cl3}$
$\ce{NH4[Cr(NCS)4(NH3)2]}$
$\ce{[Zn(NH3)4]^2+}$
$\ce{[Ag(NH3)2]+}$
$\ce{[Ni(NH3)6]^2+}$
$\ce{[Cu(NH3)4(H2O)2]^2+}$  

Several others are listed just in that one Wikipedia article, along with a fair list of references.