The only thing i'm truly confident that is going to still be around in 5 years - is github.
I would suggest that codeigniter have a page on github that are links to solutions etc on github that are officially approved.
So when someone is asking for an auth library, etc etc etc - they can be directed to one place, and its a place that all of us can be fairly confident will be around for a while. The other advantage is that there are already zillions of people searching for solutions on github every day. So it would be good exposure for codeigniter to have a comprehensive set of solutions that can be found there.
This would NOT be a list of all possible codeigniter solutions, libraries, etc. The only solutions that would be on this github page - would be approved by the codeigniter council or some group that they designate. This could actually become a validation for developers who are approved and something to work towards for people developing solutions. It would also show that codeigniter is more then a framework and there is an active developer eco-system.