R and RStudio is open source statistical analysis software that relies on community driven packages to create visualizations (ex. ggplot2). R is script heavy, meaning a programming background is highly recommended, but it offers the most flexibility in creating visualizations.
Tableau (the Public version is free for all; students have access to Tableau Desktop for free) The software enables fast creation of static or interactive infographics, including charts and maps. Tableau Desktop is currently available in the Data Services lab for educational purposes only.
All of these require submitting data to an online service. If your data is sensitive, you may be able to just upload your summary statistics.
Plotly allows users to import their dataset directly to the program and generate a wide variety of visualizations. Most are available, but some require a pro account. Free users must still have an account and save the image publicly before it can be exported. The intended purpose is interactive, D3 and WebGL charts, but static charts can be created as well. Can be used for free as long as the visualization AND DATA is made publicly accessible.
Google Spreadsheets Explore and Fusion Tables - Create visualizations from spreadsheets in Google Drive (or uploaded).
Datawrapper is easy-to-use and creates nice charts and maps for embedding in websites. Created for journalists Must give email address to get embed code. No download. Many different chart types.
RAWGraphs is an open source tool built on D3.js that lets anybody easily create a chart using a drag-and-drop system to identify axes and other chart elements. Many chart options. Allows download or embed.
Chartbuilder does not have any advanced features, but is quick and mosly easy. It can only make line, column, or dot charts and you must paste in just the data you want in the chart. Allows export as .png, .svg, or .json
Shiny is an R library for creating interactive charts and graphs.