Good alternatives: Silk-organza; Bedsheet Covers; Tea cloth or kitchen towel; Muslin cloth; Old cotton shirt. It depends on the fabric you are ironing.
What is a Pressing Cloth and Why You Should Use One
5 Pressing Rules You Must Never Break - Sew Some Stuff
The Pressing Matter of Pressing – The (not so) Dramatic Life
Why Muslin is the Better Cheesecloth - Viet World Kitchen
Guide to Press Cloths - Threads
Pressing Alternatives in the Summer – Deer&Doe • the blog
7 ways to get the most out of your garment steamer
Iron Settings - Best Settings & Heat for All Fabrics
Basics: Pressing As You Sew
Guide to Press Cloths - Threads