I don't have a long list, but here goes:

Macneil through my surname, McNeill
Gordon through my mother's maiden name
Irish National My father and his family immigrated from County Tyrone
Black Watch Universal tartan
I guess it isn't really a tartan, but I do have a Stillwater heavyweight in Black Shadow tartan.

On my list to eventually buy:
Confederate National tartan I live close to the Capital of The Confederacy and can walk out of my driveway and find relics.
US Navy I'm a Navy Veteran
USMC Tartan to honor some buddies who lost their lives in Viet Nam
Highland Granite because I like the tartan