Find all model classes that reference another via a foreign key.

fk_refs.py

from django.db.models import get_models

def fk_refs(klass):
    """Find all model classes that reference another via a foreign key.
    :type Model
    :rtype dict[Model, list[Field]]
    """
    result = {}
    for m in get_models():
        for f in m._meta.fields:
            if f.rel and f.rel.to == klass:
                result.setdefault(m, []).append(f)
    return result