Found that our table cloth was getting blown up by wind gusts, throwing off bottles and glasses etc. and remembered that we used to have little weights you could clip onto the table cloth to hold it down. Could not find them in any shop around, so just made them.
Print without support, you can add a whole set, e.g. 4 on your slicer and print the whole set. Normal speed and resolution yields good enough results.
Fill them with a marble, a steel ball, or like in my case with 3 standard 3/8 inch (9.3mm) bearing balls. Can also fill them with iron shavings, lead sand etc. If they are too light they do not do the job ;-)

Put the filling in and glue the two caps together with super glue. In case you have a rather thin table cloth, heat the clip on the object with a hair blower and carefully press the two serrated pieces a bit further together, so that they have less gap in between.