There is a surprisingly wide variety of macro lenses available, each with different capabilities and specifications that can make for an easier workflow or more unique images. This great video will give you an overview of some of the best and most popular options and the sort of images you can expect to make with them.
Coming to you from Matt Granger, this excellent video gives a great overview of a variety of macro lenses, including the following:
As you can see from just the list above, there are a ton of choices for photographers depending on their needs. I generally consider three things when picking a macro lens: maximum magnification (at least 1:1), focal length (this has huge effects on both the look of your images and the type of subjects you will be able to work with), and if it has autofocus (and thus could reasonably double as a sharp portrait lens). Check out the video above for the full rundown from Granger.