As someone who loves wine and lives alone, I've always wanted to sign up to wine testing products, but they all delivered it by the bottle, which seemed like a waste of money (and wine) given I don't drink on a daily basis and often just like a glass or two. I don't recall how I found Wine List — probably through ThingTesting — but when I saw they did deliveries by the glass I signed up, and have been a customer for 6 months now. They always source from small wineries around the world which you wouldn't normally uncover by yourself, and include tasting cards with all the info on the wine and some learning points for the drinker. Doesn't hurt that the branding is great too!
I'd love to pick whether I want white or red wine, and be able to increase the delivery frequency to 2x a month instead of only once. Have had trouble with their delivery service as well, who just refuse to use my letterbox (even though the box fits).