The TeX format is a popular academic format. TeX is a typesetting system written by Donald Knuth, especially for technical writing applications in the scientific communities of mathematics and computer science. TeX can typeset complex mathematical formulas, but is now also being used for many other typesetting tasks especially in template packages. Few people write in plain TeX any more.

LaTeX is a TeX document preparation system with programmable features and facilities for automating aspects of typesetting and desktop publishing, especially numbering and cross-referencing, tables and figures, page layout, and bibliographies. LaTeX was originally written in 1984 by Leslie Lamport and has become a leading method for using TeX
Also known as Microsoft Compressed HTML Help
CHM format is a proprietary format based HTML. Multiple pages and embedded graphics are distributed along with proprietary metadata as a single compressed file. In contrast, in HTML, a site consists of multiple HTML files and associated image files in standardized formats.
Plucker is a free e-book reader application with its own associated file format and software to automatically generate plucker files from HTML files, web sites or RSS feeds. The format is a compressed HTML archive, somewhat like Microsoft’s CHM.
TEI Lite is the most popular of the TEI-based (and thus XML-based or SGML-based) electronic text formats.
FictionBook is a popular XML-based e-book format, supported by free readers such as Haali Reader and FBReader.
Commonly known as DAISY
DAISY is an xml-based e-book format created the DAISY international consortium of libraries for people with print disabilities.

DAISY implementation have focused on two main types: audio e-books and text e-books. A subset of the DAISY format has been adopted by law in the United States as the National Instructional Material Accessibility Standard, and K-12 textbooks and instructional materials are now required to be provided to students with disabilities.
Commonly known as OPF FlipBook
OPF is an xml-based e-book format created by E-Book Systems. E-books created in OPF format are known as FlipBooks.
FlipBooks are capable of integrating multimedia contents such as video, audio, animation and images. Hardcopy and digital publications of novels, magazines, catalogs, brochures, textbooks, financial reports, company manuals, and newsletters can be created as a FlipBook.
FlipBooks are presented in a 3D page-flipping interface via an electronic book viewer / web browser, that is FlipViewerŪ.
Commonly known as HTML
HTML is the markup language used for most web pages. E-books using HTML can be read using a standard browser (e.g., Mozilla, Firefox, or Microsoft Internet Explorer), with no need for special equipment. These files can be in ASCII format or in Unicode formats like UTF-8.
HTML has the disadvantage that it is somewhat complex and offeres an additional learning hurdle before one can write in it. While it offers considerably superior layout control compared to plain text, it is significantly more difficult for the lay person to create pages in it. whatYouSeeIsWhatYouGet (WYSIWYG) html editors overcome this to a large degree, but not completely. Naturally, for one simply interested in reading something, this is not a considerastion, as the complexity of the file is behind the scenes.
However, it does enlarge the document considerably, requiring more storage space for a given work, even if images are not used to illustrate it. With modern memory being less and less expensive, this is not the challoenge it once was.
Published as an .rtf
A standard formalized by Microsoft Corporation for specifying formatting of documents. RTF files are actually ASCII files with special commands to indicate formatting information, such as fonts and margins.
Published as .pdf or .htmle
Guide as a document description was first introduced by the eToolcase in early 2001. The idea is that it provides a descriptive guide to complete any task. The eGuide provides exactly that, a guide in electronic format. Normally concise and to the point, it may be any length, containing pertinent guides to achieve the goal of the content.