Safely cleaning-up crusty ol' github forks from your repository list using python...

github_fork_cleanser.py

#!/usr/bin/env python3
#
# This script is intended to interactively help you remove stale/unwanted github forks 
# from your repo list, without accidently removing any of your actual (non-forked) repos.
# 
# The use case for this is simple: I forked wayyyy too many repos that I should 
# have otherwise 'starred', and wanted to clean-up my repository list. 
#
# Manually purging all of my forked github repos via the github.com webui would take 
# far too much effort, so I decided to automate the majority of the process. 
# 
# I didn't want to remove all of my forked repos, and I didn't want to remove 
# ANY of my personal repos, so I made this interactive script to help me 
# SAFELY dictate which forked repos that I did want purged.
#
# Author: Sean O'Donnell - https://github.com/sodonnell
#
from github import Github

gh=Github('Add your github Token here')

forks=0
for repo in gh.get_user().get_repos():
    if (gh.get_repo(repo.full_name).fork):
        forks=forks+1
        confirm = input("Remove forked repo: "+ repo.full_name +"? [Y/N]")
        if (confirm == "Y"):
            gh.get_repo(repo.full_name).delete()
            print("Deleted: "+ repo.full_name)
        else:
            print("Ignored: "+ repo.full_name)
if forks == 0:
    print("No forked repos found.")