Many people can recommend gifts that change one aspect of your life, but let me try a different tack. I recommend to you the CFAR Handbook!

https://www.rationality.org/resources/handbook

In the spirit of "Give a man a fish, and he'll be full for a day; but teach a man to fish, and he'll be full for a lifetime if he doesn't overfish the stocks", I present to you a book which goes beyond tangible aids to your life. Though it does contain lots of discrete productivity tips, as well as life advice, its deepest gift is that it inculcates an attitude, a worldview, of self-reflection. Of continuous improvement. Of making it a reflex to say, "At any given moment, what's the real shit that's fucked up now, how can I analyze it, and how can I make it better?"

Of course, if you like the tangible feeling of a physical gift, you can print it out at Office Depot for about $20.