Piplup (x2), Ponyta, Magikarp, Teddiursa (x2), Tentacool, Shellos, Infernape (caught as a Chimchar), Clefairy, Dusclops, Gligar, Hisuian Growlithe, Ursaring, Sneasler (caught as a Hisuian Sneasel), and Hisuian Zoroark (caught as a Hisuian Zorua). That makes 16.
Of those, Ponyta is the free one...