These are common options but may feel different per manufacturer.
Peach skin: smooth polyester. No stretch. Least expensive option.
2-way tricot: stretchy. A lot of people on the /dakimakura/ reddit say this is the best, but I don't personally like the samples I have ordered. It's heavy and feels like the material that cheap halloween clothes are made of, and everybody says it tears easily too.
Velvet: ?
Printers
Vograce: probably a middleman. Default quality. The most accessible. No NSFW.
JunoCreatives: terrible DPI. I sent the same images that I have sent other companies and they came out blurry and visibly pixelated.
MoeGF: dunno where they disappeared to. default quality. NSFW ok.
Guangzhou Ecai Printing: last used. Default quality. NSFW ok.