18 Scorpii, our Sun's twin
In the sky, it appears that 18 Scorpii is the star that looks the most like our Sun.
It's 46 L-Y away, has a 7 year long cycle, is 360 million years younger....No exoplanet found, so far...
But the most important star for us to study is our own Sun, of course, and studying 18 Scorpii must be part of it too (for comparisons).