Register all models that extend a certain base abstract model.

gistfile1.py

from django.contrib import admin
from django.db.models import get_models, get_app

from models import BaseModel

app = get_app('app_name')
for model in get_models(app):
    if issubclass(model, BaseModel):
        try:
            admin.site.register(model)
        except admin.sites.AlreadyRegistered:
            pass