The search for the best evidence is normally prefaced by clinical need and can come from any aspect of clinical work including:

Therapy - need to select treatments that do more good than harm.
Aetiology (Etiology) - need to address causation/ or risk factors for disease.
Diagnosis - need to select an accurate diagnostic test or interpret test results.
Prognosis - need to estimate a patients' likely clinical course over time and likely complications of a condition or disorder.
Clinical prediction - the need to predict some aspect of a disease or condition. Clinical prediction studies develop or validate rules, guides or scales for this purpose, for example, the Ottawa ankle rules.
Experience and perspectives - need to understand different perspectives and experiences of phenomena (how and why questions) to inform decisions about the feasibility, appropriateness, or meaningfulness of interventions. This evidence is generally found in qualitative studies (Hoffman et al., 2023; Williams et al., 2019)

References

Hoffmann, T., Bennett, S., & Del Mar, C. (2023). Evidence-Based Practice Across the Health Professions (4th ed.) https://www-clinicalkey-com-au.ezproxy.auckland.ac.nz/#!/browse/book/3-s2.0-C20210011524

Williams, V., Boylan, A. M., & Nunan, D. (2019). Qualitative research as evidence: expanding the paradigm for evidence-based healthcare. BMJ Evidence-Based Medicine, 24(5), 168-169. doi:10.1136/bmjebm-2018-111131