As you can see from the graph, this is not a large source of revenue. These are water, sewer and garbage disposal companies that many cities operate. The charges for the service pays all the costs, so this increases this category. Your city should have an investment policy to guide the safe investment of these funds and insure their safety. Ask to see it if you are curious.
Many cities operate traffic bureaus or municipal court systems.
As a result, we use this category to account for it. They don't often hold leaseable space for very long, but when they do, they collect rent. Other Miscellaneous is for, well, other - miscellaneous. Examples include gas tax, liquor excise tax and others. I know - only in government would you count debt as a revenue.