Paradox can show it
paradox-display-download-count is a variable defined in
`paradox-menu.el'. Its value is nil
You can customize this variable.
This variable was introduced, or its default value was changed, in
version 1.2.3 of the paradox package.
Documentation: If non-nil, adds a "Download" column to the Package
You can also use the HTTP API (https://melpa.org/download_counts.json) directly, e.g.,
$ curl https://melpa.org/download_counts.json | jq .magit
Another choice is https://github.com/emacscollective/epkg via
M-x epkg-list-packages, it shows GitHub stars and Melpa downloads out-of-box.
Don't forget it's Melpa downloads count, other elpas such as gnu elpa does not have such info, and people sometimes use Melpa through Melpa mirrors, the downloads count is not included.