Currently, if you are looking only for high-bandwidth, you should look at the scaleway.com offers, traffic is unlimited and bandwidth up to 800Mbps. But their vps are not really the best available, I consider them only the for bandwidth.
Many client's user bandwidth for media or big data transfer, so yes you can find normal high bandwidth VPS but with higher price, if you need normal guaranteed bandwidth you must pay for it -> expensive.
Bandwidth is the only resource that is some what unlimited. So most hosting provider give this option to its high usage user or to attract new customers. In most cases it a step below a dedicated line that guarantee a certain speed without interruptions.