I used to ride a relatively obscure brand of motorcycle and they had a national club with a contact list of people willing to help out others who had problems on the road. Besides their contact info, it included a list of abbreviations about what kind of assistance they could provide, e.g. Can provide a place to work on bike, have a trailer to pick up your bike, can provide a place to stay, etc. Being on the list was voluntary but had quite a few contacts in just about every state. I never had the occasion to use it, but it did provide some piece of mind when I took road trips.
I would think for cyclists, you could do something similar within a fairly small geographic area, i.e. a city and surrounding areas.