1. Path Auto
Path auto module is used to create URL aliases. A good URL aliases is essential for SEO. So this module is inevitable in any drupal development.
2.Meta Tag
SEO is one of the most required part of the website. Meta tags provides more advanced meta datas. This module includes mosts of the structured meta datas required for different search engines.
3.Simple sitemap
This module is a perfect sitemap generator. This will index all of our URL and create sitemap.xml based on our conditions. This module gives plugins to extend its functionality.
4.Ctools
This module provides a set of APIs that is required to extend our developer experience. Eg: This module provides tools to support ajax response.
5.Quick Node clone
Quick node clone module provides functionality to create the duplicate of existing nodes. This way the content editors can easily create multiple copies of the same pages.
6.Twig tweak
Twig teak modules contain a lot of beautiful functions and filters that is helpful for front end development. Eg: {{ drupal_form('Drupal\\refactor\\Form\\RefactorBlockForm') }}
7.Token
Token is a placeholder that replaces with original values while rendering .Some of the tokens are available in drupal core. This modules provides additional tokens and UI support for the development.
8.Webform
If you want to create forms, and manage it from the admin panel, this module is the best choice.
9.Search-api
If you have search in your project, this module is the best choice. This module replaces the core search module and provides API support. You can use DB, apache solr , elastic search etc with this module.
10.Paragraph
In my opinion this module is the super power of any drupal application. This is the most wanted module for the development. Paragraph gives a better way to structure our contents in a page.