How to print all possible options of a dropdown field inside of a Matrix field?
This can be done like so...

{% set matrix = craft.app.fields.getFieldByHandle('myMatrixField') %}
{% for field in matrix.blockTypeFields if field.handle=='myDropdownField'  %}
    &lt;select&gt;
    {% for option in field.options %}
        &lt;option value="{{ option.value }}"&gt;{{ option.label }}&lt;/option&gt;
    {% endfor %}
    &lt;/select&gt;
{% endfor %}