ls */

This would list the contents of all the non-hidden subdirectories in the current directory.  Since you only seem to have subdirectories with numeric names, this will show the contents of these.

The shell globbing pattern `*` would expand  to all non-hidden names in the current directory.  Adding a `/` at the end of the pattern forces the pattern to expand to only directories (since non-directories can't have `/` in their names).

With the `zsh` shell, the following filename globbing pattern would expand to only _regular_ files in each subdirectory

    */*(.)

To do something with those names that matches, you would loop over the expansion of that glob pattern:

    for pathname in */*(.); do
        # use "$pathname" here
    done

In `bash` or `sh`, you would call a small script from `find` instead:

    find . -mindepth 2 -maxdepth 2 -type f -exec sh '
        for pathname do
            # use "$pathname" here
        done' sh {} +
    
But that's really just a fancy way of writing

    for pathname in */*; do
        [ ! -f "$pathname" ] && continue
        # use "$pathname" here
    done

except that the `find` variation would skip symbolic links to regular files.