Peer Assisted Relief Through Networks of Empathetic Resources and Supports Act of 2020 or the PARTNERS Act This bill directs the Substance Abuse and Mental Health Services Administration (SAMHSA) to establish a network of peer support warmlines. Warmlines are telephone or text-based services, typically staffed by individuals who have experienced mental health conditions, that provide early intervention services, referrals, and other resources to those who are seeking mental health support but are not in crisis. To carry out this program, SAMHSA must award grants or cooperative agreements to establish centers of excellence to operate warmlines through a single, toll-free number in coordination with the National Suicide Prevention Lifeline. SAMHSA must also ensure appropriate geographic distribution of the centers. As a condition of receiving funds, the centers must, among other requirements, ensure that the individuals operating the warmlines are qualified peer support specialists and that they complete relevant training courses. In addition, SAMHSA must establish within 30 days a technical assistance center to disseminate, and enforce the use of, best practices for the operation of warmlines and must provide other support to the centers of excellence. SAMHSA must also enter an agreement with the National Academies of Sciences, Engineering, and Medicine to study best practices for warmlines.