Most ladies' scarves ( with the exception of the ever-encroaching Pashmina) tend to be somewhere between 2 feet and a metre along one square side. The iconic Hermes scarf worn by HM Queen Elizabeth is about 33 inches square. Thirty inches is a good size for a fly plaid for a shorter person and would make an excellent ( and styling) arm sling.

If you laid them out right and didn't need any (or much) allowance for hemming, you COULD get 3 12X18 placemats from a scarf, but that strikes me as a sad waste. Depending on the weight, they might be made into interesting pocket squares or pillow covers. I am sure clever people have made handbags with less fabric.

Or garter flashes, eyeglass cases, checkbook covers, tea cosies, book marks, belts, cummerbunds, hair bows, or pin cushions.

or wee pouches for medicinal herbs.