Cache invalidation to automatically update all cached template content?
I built the Cache Warmer plugin recently, which takes a blanket approach to refreshing your pages cache, by getting entries url with the .getUrl() method, and then send of batch requests to those url's.

I'm currently using it together with the Cache Clear plugin, when deploying changes to our site, and it's working well. This is a very simplistic approach to a potentially complex problem, so I would say a more granular cache invalidation/refresh strategy might be needed, depending on your use case.

However, I think there is something to be said for this approach on small to medium sites.

I want to at least add some hooks, so that you can warm up single entries/elements as well. My plugin doesn't know which pages your cached elements are living on, but there is a big chance those pages will be hit and warmed up - as long as they're located in a section, and that section is toggled in the plugin settings.