Order by reverse relationship count

If you don't have tons and tons of creators, you could do that by querying creators and re-arranging the results:

{# Get all creators and eager-load the products #}
{% set creators = craft.entries()
    .section('creators')
    .with('products')
    .all()
%}

{# Declare an array to store all related product ID #}
{% set products = [] %}

{# Build an array of all product ID occurences #}
{% for item in creators %}
    {% for product in item.products %}
        {% set products = products | merge([product.id]) %}
    {% endfor %}
{% endfor %}

{# Group by product ID #}
{% set groupedProducts = products | group(v => v) %}

{# Sort by occurence count #}
{% set sortedGroupedProducts = groupedProducts | sort((a, b) => b <=> a)  %}

{# Now you can get: Product ID | Occurences #}
{% for c in sortedGroupedProducts | slice(0,10)%}
    Product ID: {{ c[0] }} | Occurences: {{ c|length }}<br>
{% endfor %}
<hr>
{# To fetch the products, extract the keys from the above and flatten to a comma seperated list of product IDs #}
{% set productIds = sortedGroupedProducts|keys|join(',') %}

{# Query #}
{% set products = craft.entries()
    .section('products')
    .id(productIds)
    .fixedOrder()
    .limit(10)
    .all() %}

{% for item in products %}
    {{ item.title }} ({{ sortedGroupedProducts[item.id] | length }})<br>
{% endfor %}

This could probably be improved or even moved to PHP but if you have to do in Twig, it should work.