Speaking of accounts receivable, TODOs, and physical paper, I have a separate system for tracking things I have to do IRL and also things I expect to receive in future. This consists of two lists kept on single sheet of paper, which I keep on my fridge.

On the left is my TODO list, which records stuff that I need to do, for whom, and by when. Example: "groceries; party supplies; 21 December". Completed items are crossed off the list.

On the right is my "receivables" list, which records anything that someone else will supply to me. This includes tools being returned to me by friends, as well as parcels in transit to me, plus transactions that I need to be dead-certain have completed successfully (eg property tax bill). These items have an expected due date, or the latest date before I have to follow-up on what happened. For example, I would mark most online orders as expected no later than 10 business days after the order date, or 5 business days after being shipped. The expected date is updated when I learn more. When these items arrive or are complete, I cross them off.

In this way, I never lose track of packages ordered months ago (as is common for eBay or AliExpress orders), and can also schedule things months in the future that I need to deal with (eg buy concert tickets once available).