La Belle Assemblee, The Lady’s Magazine, and of course Ackermann’s Repository all published needlework patterns in every monthly issue. Many were for specific items, as you can see below in this pattern for a collar from La Belle Assemblee:
Others were just nice patterns that could be used anywhere. Here are several for your viewing pleasure. I've supplied dates where I have them…enjoy!
Muslin Patterns from Ackermann's Repository, 1813: