Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
Prezi - Welcome to Prezi, the presentation software that uses motion, zoom, and spatial relationships to bring your ideas to life and make you a great presenter.
TeXstudio - TeXstudio is an integrated environment for writing LaTeX documents.
Reveal.js - A framework for easily creating beautiful presentations using HTML
LyX - LyX is a document processor.
Google Slides - Create a new presentation and edit it with others at the same time — from your computer, phone or tablet. Free with a Google account.