Data sources for panel data
The World Bank Enterprise Surveys (https://www.enterprisesurveys.org/en/enterprisesurveys): You need to create an account, the process is fairly simple. Once you have an account, you can search for survey type "Panel Data" in the Section Survey Data sets. Characteristics: country panel data surveys with typical time dimension equal to 3, the number of surveyed enterprises vary per country. The sample is obtained by means of stratified sampling at several stratification levels (https://www.enterprisesurveys.org/content/dam/enterprisesurveys/documents/methodology/Sampling_Note.pdf).