1. (FREE) Akismet Anti-Spam - this is almost as a wheel for a car, it does not slow down your site, it's small, but quite good works with spam comments, so after installing your WordPress leave this enabled.
2. (FREE) All 404 Redirect to Homepage - This is quite good if sometimes to forget to add 301 to an article which changed URL, so you won't lose any link juice.
3. (PAID) Amazon Affiliate for WordPress -
https://getaawp.com/ - this is a really great plugin for building Amazon Product rich websites. I'm always including products within the text and after the article, it has amazing Conversion Rate and looks amazing.
4. (FREE) AmazonJS -
https://wordpress.org/plugins/amazonjs/ - I was using this plugin since I started to learn about Amazon Niche sites and it's working great even it's abandoned. I'm always including product with this plugin under the images and it converts also amazing. I got ~40% of product sales only with this plugin alone.
5. (FREE) Attachment Pages Redirect -
https://wordpress.org/plugins/attachment-pages-redirect/ - I don't use any stupid SEO plugins so I need to Redirect attachment pages manually. I was doping it by adding a small image.php file in the root of my WordPress before, but it disappears after each update of the theme, and this plugin does the same exact thing. In case you don't know why you need this - attachment pages are the page which opens when you click on an image (if you set it in the settings) and it's just a post page with just an image. Google considers it as a thin content page and if you have thousands of images you can get a thin content penalty just by using these pages.
6. (FREE) Contact Form 7 -
https://wordpress.org/plugins/contact-form-7/ - It's exactly what the title says.
7. (FREE) Contextual Related Posts -
https://wordpress.org/plugins/contextual-related-posts/ - For better internal linking, this shows ~5 related posts at the end of an article.
8. (FREE) Disable Google Fonts -
https://wordpress.org/plugins/disable-google-fonts/- It disables Google Fonts and speeds up a site quite a lot
9. (FREE) External Links -
https://wordpress.org/plugins/sem-external-links/ - I'm using this to nofollow all outgoing links and allow only specific links to be d0f0ll0w
10. (FREE) Jetpack - I'm using this only for Site Stats and all other features are disabled as they slow down your site for 60% and are stupid features.
11. (FREE) Redirection -
https://wordpress.org/plugins/redirection/ - I'm using this plugin so I can 301 redirect URL changes.
12. (FREE) Remove Category URL -
https://wordpress.org/plugins/remove-category-url/ - This plugin removes stupid "category" from the URL like - page.com/category/cats.
13. (FREE) Schema -
https://wordpress.org/plugins/schema/ - I'm using this for SiteLinks and rich snippets.
14. (FREE) Shortcodes Ultimate -
https://wordpress.org/plugins/shortcodes-ultimate/ - I'm using this because it's rich in featured and shortcodes.
15. (FREE) TinyMCE Advanced -
https://wordpress.org/plugins/tinymce-advanced/ - This is must have for all WordPress websites and are not questionable IMHO.
16. (FREE) Two Factor Authentication -
https://wordpress.org/plugins/two-factor-authentication/ - I'm quite careful about my websites as well as for security so 2FA is must have for me!
17. (FREE) Wordfence Security -
https://wordpress.org/plugins/wordfence/ - Also Good Firewall and overall virus protection from hacked plugins or cyber attacks.
18. (FREE) WP Word Count -
https://wordpress.org/plugins/wp-word-count/ - For counting how many words I have posted and how many are in the draft.
19. (FREE) WPS Hide Login -
https://wordpress.org/plugins/wps-hide-login/ -Also a security trick - hide your default wp-admin with something more related to you. This is good for bruteforce attack protection.
And that's it. I'm using almost the basic plugins and doing it for all my sites. Of course, I could live without some of these but sometimes it's easier to install a small plugin that trying to achieve the thing without it.!