Wordfence for security
Beyond the normal security stuff, it will also send me an email every time someone logs into my site, or when a plugin / theme is out of date and needs an update. (Updates often fix holes, so this is important). It has a free and premium versions.
Another option here is Akismet. Use them both.
Monarch for opt-ins
This is part of the Elegant Themes’ Divi Package (which is included in the Divi license that comes with our themes). It will let you use short codes, popups, or inline text (along with other features). It’s smooth and easy to use.
Bloom for sharing
Like Monarch above, this is also an Elegant Themes plugin (and included in our Divi licence themes). I’ve tried a bunch of sharing plugins. But this one has the most features and lets me control both the position and look of my social buttons the best.
Yoast for SEO
This helps you optimize your site for SEO purposes. There are a lot of SEO plugins out there. If you’re deep into SEO your needs might be different. But if you’re new to it, this is a solid place to start. Free and premium versions.
WP Fastest Cache for Site Speed
This is a free plugin, but there’s also a premium option. This is one case where the premium is hands down worth it. If you’re not comfortable editing code, or if you’re not familiar with the ins and outs of what makes for a fast site (i.e. one that ranks well in google), this does a great job. I’ve had sites that have ranked in the red (with Google developer tools), and then after using the premium plugin, they were in the green.
How you collect data (and then what you do with it) is becoming a bigger and bigger issue. This is an easy to use plugin that will give you a good banner. Quite customizable. And then it will help you create a /cookie page.
Google Analytics for Metrics
If you’re going to know which pages are performing well (getting the highest clicks, which are most evergreen, or even, how people are finding them), Google analytics is the standard tool here. And it’s free.
BackUpWordPress for Automatic Backups
This one’s a bit of a no-brainer. It’s free. And it’s automatic. If something happens, you’re covered.