These are the resources I have found for scripts for commedia plays. It must be noted that all of these are of much later origin than the original commedia dell ‘arte, as it was purely improvisational theater.
Scenarios of the Commedia dell’Arte – Flaminio Scala ; translated by Henry F. Salerno (New York University Press, NY/1967) of 50 plot structures Scala published in 1611
For the Love of Three Oranges – A Play for the Theatre That Takes the Commedia Dell’arte of Carlo Gozzi and Updates It for the New Millennium by Hillary DePiano, Carlo Gozzi
The Green Bird – Carlo Gozzi; John Mitchell
The Servant of Two Masters (Plays for Performance) by Carlo Goldoni adaptation by Dorothy Louise (Ivan R. Dee, Publisher; New Ed edition 2003)
The Triumph of Love – by Pierre Carlet de Marivaux; not a commedia play but has commedia based characters