PubMed has a Medical Subject Heading (MeSH):

Methods - A series of steps taken in order to conduct research.

methods[mh]  >500,000 results

methods[majr] >50,000 results

Combine Methods as a subject heading with your topic

bereavement[mh] AND methods[mh]

PsycInfo has a search filter for Methodology. Select from the options to view articles that use a particular type of methodology.

telemedicine AND "mental health" with Methodology filter: non-clinical case study

Select any of the Methodology type options and combine with a search on your topic

all "nonclinical case study" results ~25,000 results