A service I would be willing to even pay a little bit/month for:
Subscription Management as a Service
I'll share all of my passwords for various subscription accounts like streaming services etc, then on the beginning of the month, send me a report of which ones I have that are active, which are suspended, etc., and if I want to change, pause or cancel anything, I just unclick the checkbox and the unsubscribe/change happens automatically.
Bonus points if it can also manage the annual call Comcast and badger them into giving me a discount song and dance ...