I’ve never much cared for Google PageSpeed Index scoring since, well, it makes no sense and hates WordPress. That said, Envato had a sale on Black Friday. They promoted the Borlabs Cache plugin, which I had never heard of.
Mind you, my site is already cached with Redis, Nginx proxying, gzip, levies browser caching, etc. I also own licenses for most major caching plugins (including WPMU Dev Hummingbird), but none of them can compete with Redis. However, it made me curious so I tried it.
By simply installing Borlabs Cache and enabling HTML compression, my Google PSI score went from a 75% (C) to an 86% (B).
I highly recommend the plugin. It is easy to use and yields excellent results.
My only complaint is that they don’t have an unlimited developer license. They do offer volume discounts, though, and their customer service is very helpful and excellent.
If you can’t Redis and Borlabs doesn’t work for your site, I also highly recommend Comet Cache Pro (which does have an unlimited license). The configuration is more intense but it is the best WordPress caching plugin that I’ve used after the aforementioned.
Of course, if your web host doesn’t Redis, you should probably talk to me about hosting your site.