Heartstone
The Heartstone is an item crafted with 3 amethyst and 1 heart of the sea. It comes in pairs, and allows the player to seek out another player to whom they've given the second stone. Right-clicking the stone sends a particle trail in the direction of the player.
Now you can find friends without hitting f3 once!
The Heartstone works in three stages: 0-999 blocks, 1,000-9,999 blocks, and 10,000+ blocks. As the distance between people increases, the particles indicating their direction will shrink and lower in pitch.