Let's just say, I bought the 4 yards of Caledonia from The Scottish Weaver remanant page. I also bought some Carolina tartan (not really universal, but an official state tartan of both North and South Carolina.

As for the "generally available" ones, I like the subtlety of Black Watch.

I also like Highland Granite and many, many more.

Wishing I had more money to get more and more tartan material,