If 2017 was the year of the Instant Pot, 2018 was the year to gift or get a weighted blanket — a duvetlike bed cover weighing from five to 25 pounds. Never heard of one? Neither had I, until I got this assignment. But they are a hot commodity. For example, the Gravity Blanket, which began as a Kickstarter campaign in 2017, reports $16.5 million in sales for 2018.