Ya. I have been working on the web development since I was in Collage. But there are a lot of tags that I never used in my project.

Here is one article that I found in internet. You will see the following tags which are (probably) never used in our web applications that we developed. Chect it out and hopefully, it will be useful for some cases.

• <address>
• <q>
• <optgroup>
• <acronym> or <abbr> combined with the title attribute
• <fieldset> and <legend>

Link: 5 HTML elements you probably never use (but perhaps should)