I will keep it short, just mention the names of some of the plugins I use and apply to all new blogs I create for my friends and me.
Just mentioning the names in case of Free Plugins, you can search it from the Wp Plugins Directory and look at the features.
2FAS Light - Google Authenticator: For 2 Step verification. My favorite one was Clef, but they have stopped their services recently, so I had to look for an alternative. Out of all the good and fancy ones, I chose this one. Its free, and lightweight, and does its job.
Ad Injection: For showing Advertisement Inside the Content. I have tested with other alternatives of this plugin that does the same job, but ultimately sticking to this plugin. It has a lot of customization, like how many ads to show based on the no of words of the post, which is very useful.
Bloom: Paid Email Optin Plugin. The best of all the options I tried. If you can couple it with Mailchimp, then your are all set up. Its simply the best combination to get better conversions and manage your subscription list.
EWWW Image Optimizer: My favorite plugin to losslessly compress images as soon as you upload them automatically. Its free. It keeps the original image on server, just creates a compressed copy of it so you won't lose the original one.
Google Analytics Dashboard for WP: For displaying Google Analytics stats on your Wp Dashboard, I don't always get time to visit GA site, so this helps a lot to reduce our effort.
UpdraftPlus - Backup/Restore: The best free plugin to automatically backup your Wordpress website including your posts and the whole wp database, to Google Drive everyday. I wrote an article myself on How to automatically backup and restore your Wordpress site with Updraftplus.
Wordfence Security: The Free Security plugin for your wp site. Protects from hacker attacks. You can check live traffic movement on your website, location and ip of your visitors, and block any ip from visiting your website. It has some good and unique tools.
WP Rocket: Again, a paid plugin, But, definitely the best cache plugin out there. I tried and tested with all the free and paid cache plugins, this one is simply the best. Compared to wp super cache and wp total cache, the two market leaders, this one will make your website load in shorter time.
Yoast SEO: A must have plugin, not becase it does give you instant boost in SEO, but, it collects some important tools you will need. The post meta box editor is one of the best ones, it basically allows you to fully check the meta output and edit accordingly (WYSIWYG). Other important tools are the xml sitemaps creator, social accounts etc. You will know when you fully explore it.
That's all. I gave the list of WP Plugins I use and I always recommend my friends to install. Yes, even without these, you will probably do very well, but these will make your WordPress experience better.
Thank You for reading. Do share this page with your friends out there.
PS: Don't forget to use a CDN on your website. Its extremely important and will give further boost to your page loading speed. I recommend Cloudflare.