Sigil alternatives
Builds and edits ebooks in the EPUB 2 and EPUB 3 formats, giving control over markup, metadata, styling, and table of contents
A comprehensive PDF solution to view, print, annotate, as well as create, edit, convert, digitally sign, encrypt, export and publish PDF files
Page layout and desktop publishing software for producing print and digital documents such as brochures, magazines and ebooks

A freemium PDF tool for viewing, annotating, filling out forms, and signing PDF documents

A desktop publishing (DTP) application, designed for layout, typesetting, and preparation of print or digital publication files for professional-quality image-setting equipment

Allows editing, creating, and converting PDF files, including scanned documents and fillable forms
All-in-one app for photo editing, vector graphics and page layout, with a single shared file format
A cross-platform WYSIWYG web and EPUB editor based on the Firefox rendering engine, supporting HTML5, CSS3, and SVG editing
Professional page layout software for creating documents, from books and magazines to marketing materials and social media templates