Toya from Made by Toya shares a free pattern for making a pair of toddler girl panties. She used this pattern and a stack of outgrown onesies to make new panties for her young daughter. If you don’t have onesies that are big enough for your pattern, you could use any knitwear (t-shirts, etc) that you no longer need. Her free pattern fits a little girl 2-3 years old, though you could probably adjust the pattern up or down a size as needed.
Click below for her free pattern and tutorial:
Thrifty knickers: A KCW upcycling project with pattern and tutorial, by Made by Toya
[photo from Made by Toya]