Available plugins:

Compress css & js on-disk
This plugins add on-disk compression of static CSS & JS files.
Does not require mod_deflate.
Features:
  • Compressess JS & CSS files, stores compressed versions on disk
  • Adds caching HTTP headers
  • For selected mime types, delegates "404 Page not found" to cheap httpd processing, instead of expensive WordPress processing. No one will see the WordPress "404 page not found" anyway, i.e. when CSS file is lost.

Optimize images
This plugins enables simple, but efficient, lossy image optimization. Optimizations are done by pngquant, jpegoptim, giflossy (have to be installed on server)
Features:
  • Optimizes uploaded media files

Reverse Proxy Protect
This plugins redirect requests coming not via reverse proxy. If request does not come via reverse proxy with secret http header set, it's redirected to home url.
Features:
  • Optionaly rewrites REMOTE_ADDR to X-Forwarded-For if secret header value match

Debug Bar Memory
This plugin helps to find out what consumes memory in WP at different execution stages
Features:
  • Logs memory usage and particular SQL queries