From an 1886 children’s magazine, this fanciful letter F image was used to adorn one of their pages. Now, you can use it to adorn one of your own projects as it is easily in the public domain virtually everywhere.
It is a bit on the small side but I think that just makes it prettier to use with plain text. The lower-case F reminds me a bit of a heavy Old English sort of font. It has areas of light and dark and is decorated with delicate scrolls and curls.
This image is copyright free and in the public domain anywhere that extends copyrights 70 years after death or at least 120 years after publication when the original illustrator is unknown.