Based on your screenshot, the SQL stuff was installed on 9/10/2013. I would sort the list by Install Date and see what else was installed on that day--that should give you a pretty indication of what installed the SQL components.
But, if you've already determined that this was VS (it does, by default) then yeah, you should be safe to uninstall both (VS and the SQL components). I'd start with VS and see if it prompts you to get rid of SQL at the same time--I'm not sure whether it does, it's been years I've uninstalled VS from a machine.
My suggestion: If you're gonna play around with massive tools such as these that install lots of stuff everywhere, including services that run constantly, and you're not sure whether they're tools you're going to keep, you should use VMs. I suspect VS doesn't do that good of a job cleaning up after itself, even after you've deleted everything from the uninstall list (I've seen SQL, for example, leave behind well over a GB worth of disk space in installation log files alone--not to mention database files and transaction logs) . If you run all of this in a VM instead, you can be certain that deleting the VM won't leave behind any files you no longer need.
Of course you need more space to get VMs running, but they help tremendously in keeping your host OS in a pristine state.