minimal

Smallest possible document class for testing whether LaTeX is working.

article

Short documents such as articles, papers, assignments, manuals, & documentation. No chapters.

report

Longer documents such as reports, theses, & dissertations. Supports chapters.

book

Books. Supports front matter, main matter, back matter, chapters, & indexes.

letter

Writing letters. Includes sender, recipient, opening, closing, & signature commands.

slides

Legacy presentation slides. Largely replaced by beamer.

beamer

Modern presentation slides with overlays, animations, navigation, & themes.

memoir

Advanced replacement for book & report. Includes many built-in layout & publishing features.

standalone

Creates a single figure, diagram, table, or page that can be included in another document.

exam

Exams, quizzes, worksheets, & answer keys.

proc

Conference proceedings.

scrartcl

KOMA-Script version of article with improved typography & European layout conventions.

scrreprt

KOMA-Script version of report.

scrbook

KOMA-Script version of book.

scrlttr2

KOMA-Script letter class.

extarticle

Like article but supports larger base font sizes (14 pt, 17 pt, 20 pt).

extreport

Like report with larger font sizes.

extbook

Like book with larger font sizes.

ltxdoc

Writing LaTeX package documentation.

tufte-book

Books styled after Edward Tufte, with wide margins & side notes.

tufte-handout

Handouts styled after Edward Tufte.

elsarticle

Elsevier journal articles.

IEEEtran

IEEE journals & conference papers.

acmart

ACM journals & conference papers.

revtex4-2

Physics journals (APS, AIP, etc.).

amsart

American Mathematical Society articles.

amsbook

American Mathematical Society books.

amsproc

American Mathematical Society conference proceedings.

llncs

Springer Lecture Notes in Computer Science.

svjour3

Springer journals.

apa7

APA 7th edition papers.

moderncv

Curriculum vitae (CV) & résumé.

resume

Simple résumé documents.

thesis

University theses & dissertations (varies by package).