What type of line (string) is on old reels?

Generep Weed Eater Dual Line String Trimmer Replacement Spool for Greenworks .29242/29082 27ft 065-Inch Dual LineCompatible with Greenworks Models

Antique Vintage Garden String Line Marker Reel Winder/Pin Wrought

EXPAND-IT 18 STRING TRIMMER ATTACHMENT - RYOBI Tools

VINTAGE CARPENTERS CHALK LINE REELS - DANDEE REEL - antiques

Kirschbaum Xplosive Speed 17/1.23 String Reel - 660

primitive vintage rope winder, old wood hand winder / clothesline reel

Is this bad??? Bought a new fishing pole after a few throws seen

Line Reels Empire Level - Built On Trust

Strings

Bon Tool 500-ft Neon Yellow Nylon Mason Line String in the String