Background: SARS-CoV-2 has resulted in widespread awareness of health workers' work realities and their mental health impacts, and corresponding unprecedented research effort. Reviews of the quantitative literature on mental health of clinical skilled healthcare personnel in low- and lower-middle income countries (LLMIC), however, point at quality issues in the pre-pandemic literature. We used the evidence generated in the context of one pre-pandemic review to understand methodological strengths and weaknesses in detail, with the aim of distilling recommendations for future research. Methods: Our study used the literature identified in a systematic search from inception to the end of 2020, in English or French language, in MEDLINE, EMBASE, PsychINFO, Global Health, and CAIRN. Following a scoping review approach, we extracted and charted data on key study characteristics as well as on study quality. In regard to the latter, we developed nine quality criteria on the basis of existing quality checklists, but expanding on issues of particular relevance to the measurement and interpretation of levels of mental health or illness. We collated the charted data in descriptive fashion. Results: We included data from 152 studies, which assessed a range of mental health outcomes, although most burnout. Most studies were conducted in India, Nigeria, Pakistan, or Egypt, in urban secondary- and tertiary-care settings. We judged only 20% of studies as of high quality due to shortcomings particularly regarding sample representativeness, context-specific measurement tool validity, and reporting of methodological detail. Conclusion: We conclude that despite its impressive size, we can learn comparatively little from the body of literature up to the end of 2020 due to narrow study focus on specific settings and strong limitations in quality. Based on our findings, we outline areas for expansion, methodological improvement, and standardization of reporting in future research. PROSPERO Registration: CRD42019140036.