Essential tracking tags you must have in your Google Tag Manager container are –
1) Conversion Linker Tag: A conversion linker tag is helpful for linking the user’s click on any of your business’s promotion or Ads with the interaction of them on the website
2) Event Tags: Very important type of tags which will help you in tracking even the smallest of the visitor interactions on the website.
3) Social Outbound Links: These tags will help you track how many people actually visited your social handles through your business’s website.
4) PDF Download tags: This type of tags will help you in understanding which of the document/whitepapers available on your website were downloaded how many times.
5) Form Submits: Most common type of tracks done on website for the purpose of conversion tracking and more. These tags can also help in setting up “Event Goals” in Google Analytics which will make your GA setup easier.
6) Video tracking: If you have a lot of videos on your website, you need to have video tracking tags on those to track the visitor’s engagement with the videos on the website.
7) Scroll Tracking: Scroll tags are very important for brochure-ware websites which are more focused towards engaging and educating the visitors with content.