Background: I encountered an interesting Twitter thread where someone was trying to figure out how to mass unblock. This gist is adapted from one of the replies. Essentially it uses api oauth tokens to get that user's block user list and then unblocks them one by one.

simple_mass_unblock_twitter.py

import json
import oauth2 as oauth
import requests
import urllib
 
CONSUMER_KEY = "CHANGEME"
CONSUMER_SECRET = "CHANGEME"
ACCESS_KEY = "CHANGEME"
ACCESS_SECRET = "CHANGEME"
 
def get_user_block_list():
    consumer = oauth.Consumer(key=CONSUMER_KEY, secret=CONSUMER_SECRET)
    access_token = oauth.Token(key=ACCESS_KEY, secret=ACCESS_SECRET)
    client = oauth.Client(consumer, access_token)
 
    block_list_endpoint = "https://api.twitter.com/1.1/blocks/list.json"
    options = "?skip_status=true&include_entities=false&cursor=-1"
    block_list_endpoing = block_list_endpoing + options
    
    response, data = client.request(block_list_endpoint, method='GET')
    user_list = json.loads(data)
    blocked_users_list = []
 
    for user in user_list["users"]:
        blocked_users_list.append(user["screen_name"])
 
    if user_list["next_cursor"] != 0:
        more_accounts_to_get = True
        current_cursor = user_list["next_cursor"]
        while more_accounts_to_get == True:
            block_list_endpoint = "https://api.twitter.com/1.1/blocks/list.json"
            options = "?skip_status=true&include_entities=false&cursor=" + str(current_cursor)
            block_list_endpoint = block_list_endpoint + options
            
            response, data = client.request(block_list_endpoint, method='GET')
            user_list = json.loads(data)
 
            for user in user_list["users"]:
                blocked_users_list.append(user["screen_name"])
           
            if user_list["next_cursor"] == 0:
                more_accounts_to_get = False
            else:
                current_cursor = user_list["next_cursor"]
    return blocked_users_list
 
def unblock_user_list(blocked_user_list):
    consumer = oauth.Consumer(key=CONSUMER_KEY, secret=CONSUMER_SECRET)
    access_token = oauth.Token(key=ACCESS_KEY, secret=ACCESS_SECRET)
    client = oauth.Client(consumer, access_token)
 
    unblock_list_endpoint = "https://api.twitter.com/1.1/blocks/destroy.json"
   
    for screen_name in blocked_user_list:
        print("Now attempting to unblock: " + str(screen_name))
        payload = {"screen_name": screen_name,
                   "include_entities": False,
                   "skip_status": True}
        response, data = client.request(unblock_list_endpoint,
                                        body=urllib.urlencode(payload), 
                                        method='POST')
    return "Success!"
 
if __name__ == '__main__':
    list_of_blocked_users = get_user_block_list()
    un_block_result = unblock_user_list(list_of_blocked_users)