Super Camera Anchor

Any GameObject can be anchored to a camera with Super Camera Anchor! It's the perfect tool for creating a UI without having to use Unity's UI system.

–Online Documentation

Total Control
The anchor point is set relative to screen space, and can be given an additional offset. You can even automatically set the object to face the camera, too.

Say bye-bye to Unity UI
Worried about performance? Super Camera Anchor has both automatic and manual update modes. If the object you're anchoring is a child of the camera, Anchor To Screen won't do unnecessary calculations to keep its position.

Just Works
Works with both perspective cameras and orthographic. Replaces Transform in the editor to avoid clutter.

–Online Documentation