Since you probably got a lot of good plugin ideas here, here is my advice. Use a little plugins as possible. Don't bloat your website with unnecessary plugins. I do use 3 or 4 plugins almost always. Including caching plugins, image optimization, the classic editor, woocommerce (when needed). But I try to avoid plugins. Beside that it adds bloat, they can be a security risk if the plugin wasn't built correct or hasn't been updated in a while.
To optimize images for free (and a lot of more good features), try Clearfy.I'm using Jetpack for it's photon feature only (Image optimized and CDN), all other features disabled. I know that installing Jetpack for that feature only might be too much but TBH I can't find any other plugins to replace it (free, automatically optimize). You guys have any recommendations?
Other plugins I install on every site are:
Cache Enabler
Either Sucuri or Wordfence
Disable XML/RPC
Yoast