How To Do - Marker Box

I am working on a game in space, where space fighters fight each other.
I have a working radar, showing where the enemy and friend ships should be, but because space is very dark and distances are sometimes a little bit far, i would like to mark my gameobjects with something like a non-lightened-box.
I am thinking of a surrounding box, something that can be used as a mark on my screen to show: there really is a ship.
My question:
Is there something know what is, what i am trying to build ?
And if i can’t find something like this, how would i try to do it myself ?

something like these target/locked in boxes?

could try with these, to convert world position to screen pos, and place GUI/UI element on ship position:

That looks exactly like what i am looking for. I’ll review it, thx !