If it's a
sign such as attached pics you can easily make your own. Village Pharm, which was very temporary, is just grommets every 6" and a couple dozen feet of paracord. PRC, which was an economy way to o semi permanent, had pole pockets around perimeter of banners. I placed a patch of gorilla tape over the screws and filed down the sharp corners. Slid EMT poles thru pockets and tensioned it down with heavy duty zip ties. PRC is in a high wind area and the install lasted longer than the color fade on the
sign.
For bollard covers, well duh, it's coroplast and DS tape. I've never had to temporarily cover a parking
sign, so I don't have a clue.