Some of the most popular names include Mountain Warehouse, Merino & More, Helly Hansen, Brass Monkeys, LAPASA, Smartwool, Woolly Henley, Icebreaker Oasis, Minus33 Chocorua and more. When you shop from these brands, you can be sure of purchasing the top-quality base layers made of Merino wool, as well as great customer support and fast shipping.