Starting Plugins List

Basics:

Automatic Updates on Admin Side or just add this code

Security: All In One WP Security & Firewall or iThemes Security

https://wordpress.org/plugins/wordpress-seo/

http://www.advancedcustomfields.com/

https://wordpress.org/plugins/backupwordpress/

https://wordpress.org/plugins/ricg-responsive-images/

If there’s Lots of Content

https://wordpress.org/plugins/relevanssi/installation/

Contact Form

https://wordpress.org/plugins/contact-form-7/

https://wordpress.org/plugins/contact-form-7-to-database-extension/

https://wordpress.org/plugins/contact-form-7-honeypot/