List authors on front end by total number of entries
You could do something like this:

{# Fetch entries + authors and group by author id #}
{% set entriesByAuthors = craft
    .entries()
    .section('itbuzz')
    .limit(null)
    .with('author')
    .all() | group(e =&gt; e.author.id) %}

{# Build an array with authorId and entry count for each that we can sort them #}
{% set leaderBoard = [] %}
{% for author, entries in entriesByAuthors  %}
    {% set leaderBoard = leaderBoard | merge([{'author' : author, 'count' : entries | length}]) %}
{% endfor %}

{# Build an array of user ids only sorted by entry count and extract the top 8 #}
{% set authorIds = [] %}
{% for result in leaderBoard | multisort(e =&gt; e.count, direction=SORT_DESC) | slice(0,8) %}
    {% set authorIds = authorIds | merge([result.author]) %}
{% endfor %}

{# Fetch users based on our sorted and sliced array of ids #}
{% for author in craft.users().id(authorIds).all() %}
    {{ author.firstName }} - {{ author.lastName }}&lt;br&gt;
{% endfor %}