It would be comfortable or convenient when text search in the top search bar start with the character "[", the tags containing the text after "[" character are suggested.
It is true that this approach was made several years ago here, but the Stack network has evolved, I consider it convenient to suggest the existing tags that could be the most popular, similar to what happens from the tags field when formulating a new question.
[followed by one or more letters in the search bar. IOW, similar to what happens when you start typing in the tags field of a question.