Letter to Yourself - Send a physical letter to your future self
Felt for iPhone - Handwritten cards for the modern world
Future Me - Send an email to your future self
43 Layers - Marketplace for custom gifts and decorations
Letter to my future self - Letter to my future self is a prominent email scheduling service that gives you the opportunity to create a letter with goals and thoughts for your future self and schedule a date for sending it.
GiftStarter - Crowdfunded gift-giving and gift concierge