Yeah, in addition to Kindle (.azw) there's also .epub, .pdf, .mobi, .odf and others.
I have many Kindle, pdf, epub and mobi cookbooks.
This is from Calibre's website—a popular e-book manager:
"Input Formats: AZW, AZW3, AZW4, CBZ, CBR, CBC, CHM, DJVU, DOCX, EPUB, FB2, HTML, HTMLZ, LIT, LRF, MOBI, ODT, PDF, PRC, PDB, PML, RB, RTF, SNB, TCR, TXT, TXTZ
Output Formats: AZW3, EPUB, DOCX, FB2, HTMLZ, OEB, LIT, LRF, MOBI, PDB, PMLZ, RB, PDF, RTF, SNB, TCR, TXT, TXTZ, ZIP"