For 25 years, the National Science Foundation's Alliances for Graduate Education and the Professoriate (AGEP) program has been supporting efforts to broaden participation and meaningfully diversify the Science, Technology, Engineering, and Mathematics (STEM) postdoctoral and faculty ranks. To examine the structures and strategies carried out by NSF AGEP programs, a thematic taxonomy was developed based on awardees operating from 2013-2021. The classification of 27 NSF AGEP programs, spanning across the U. S. and representing Institutions of Higher Education from coast to coast, identified the interventions and activities undertaken at the individual, cohort, and institutional levels. Findings from the thematic taxonomy are accompanied by a discussion of both the strengths of AGEP alliance models in higher education, and critical gaps that persist for minoritized STEM scholars. Clear commonalities across all alliances were found. For example, the impact of the COVID-19 pandemic affected all daily operations at colleges and universities. The shared aims of these separate alliances also revealed novel advances. Accordingly, a case study was conducted and the TxARM AGEP cohort members provided useful insights regarding their social learning dynamics and crises of belonging from the cohort members' level.