Is there a list of altcoin communities that has the most active developers? In terms of updating the codebase, bug response, new features etc.

Who are the front runners that at least update at least once or twice a month? 

If an altcoin that doesn't even update their codebase or bug responses within a month should not qualify.
Coin Gecko (https://www.coingecko.com/en) has all sorts of metrics on what coins have active communities/developers. I'm not sure how exactly they measure each of these things, but it may be what you're looking for.