This ^^ is the standard H-brace that I see at the corners of agricultural fences all over the southeast, and sometimes in the middle of a long stretch of fencing.
The “twitch stick” for the wire tightening of this brace just works. So simple and yet so effective.
Operating at a slightly lower level of performance is the so called “kiwi brace” which employs the same principle, just not quite as much tensioning ability as the H-brace.