Like many great creative unions, the designers Mona Koochek and Tania Martins of the Toronto-based women’s label Markoo met completely by chance. In 2012, Koochek was looking for something to wear for a gallery fund-raiser — and made a beeline for Carte Blanche, “the coolest store in downtown Toronto.” The shop, which shuttered the next year, was co-owned by Martins and was known for stocking niche brands such as Camilla Skovgaard and Jeremy Scott.