To add a few:
LFC: Tim Cadwallader (Turbos)
HBHS: Ben Tameifuna (Racing92), Marino Mikaele-Tu'u (Highlanders/Magpies), Jacob Devery (Magpies), Folau Fakatava, Devan Flanders, Lincoln McClutchie, Danny Toala and Kianu Kereru-Symes all have Magpies contracts; I don't have a link, but didn't someone say Josiah Tavita-Metcalfe has a contract as well?
Not sure about contracts, but I think Jeriah Mua has at least an academy contract with BOP, but it could also be a full Steamers contract. I think there was another Hastings player at BOP. Maybe Antonio Mikaele-Tu'u has a contract with Waikato, but not sure.
Kini Naholo has been signed by Taranaki on an academy contract
NBHS: Pouri Rakete-Stones
St John's: Jonah Lowe (he went there, before going to King's)
There have been quite a few professional players who went to Te Aute College at some point.
I don't know many, but - apart from Cory Jane and Piri Weepu, who have retired - I can think of Billy Rophia (Dax, in France's Pro D2 comp).