The Etoile store in the galleria has tabac and royall.
British Isles in Rice Village has TOBS, Trumpers, and some other stuff.
I went to a barber supply called Findlay & Sons just outside the Loop on Kirby and grabbed some Osage Rub. They had a fine selection of Pinaud products and some others that I don't recognize.
Kuhl-Lindscom on West Alabama (just across a sidestreed from Whole Foods) has Musgo Real, SMN, and AdP products. They may have more than that but the wife was done shopping.
None of that is in N. Houston.