I don't know if any of you have tried the new Gmail App, but before you knock it, realize the search function is amazing. Keeping that in mind, I have managed to utilize the new built-in shortcuts feature for advanced searching In Gmail.

Here is a screenshot of some basic syntax

If you have heard of TextExpander, you shouldn't have a problem making these next shortcuts.

Example:

Phrase: has:attachment
Shortcut: hasatt

Phrase: hasatt
Shortcut: hast

Phrase: hast
Shortcut: has:

These will show you that typing a small amount of letters can suggest a shortcut, which can then suggest another shortcut, and so on.