Gmail search keywords

I have Gmail account since year 2005.
And searching in my inbox takes sometimes lot of time and is pretty difficult.

I found a nice post, which makes search in Gmail inbox much simplier.
How to Search Mail in Gmail
Some useful examples:

subject: – Search the Subject line.
Example: “subject:bahamas” finds all messages with “bahamas” in the Subject.
from: – Search Gmail for sender name and email address. Partial addresses are okay.
Examples: “from:heinz” finds all messages from “heinz@example.com”, but also all messages from “your.heinz@example.com”; “from:me” finds all messages sent by yourself (using any address set up for use in Gmail).
has:blue-info – Search Gmail for messages with a blue i.
before: – Search Gmail for messages sent before a date.
Example: “before:2005/05/05” finds all messages sent or received on May 4, 2005 and earlier.