National New Play Network (NNPN) - A consortium of theatre across the country with a special focus on new plays. In Philadelphia, InterAct Theatre Company is a founder and Core Member. Azuka Theatre is an Associate Member.
New Play Exchange - Searchable database of new plays created and run by the National New Play Network (NNPN). Playwrights create a profile and upload plays to be read. Modest annual subscription fees.
The Kilroys - List of the best un- or underproduced plays by women, trans and non-binary playwrights. List suspended in 2020 and replaced with Web 2023.
The Playwrights' Realm - Offers support to developing playwrights. Lists past productions of new plays. (You have to dig a bit.)