The most common features I remember needing prefixes for were features such as flexbox, border-radius, box-shadow, etc... but now they are supported. With more users switching to more powerful browsers like Chrome and Firefox and away from IE, are there still features now that haven't been fully supported and require prefixes?
There is a great site which allows you to check out support of any css property by most modern browsers. It also shows info about vendor prefixes (if they are needed). This site is named "Can I use" - http://caniuse.com