Go check your Google Play Store settings. There's an 'Add icon to Home Screen' setting there. And if you've installed a third party launcher, there may be something in the launcher's settings to have that trickle down to the launcher.
But the 'suggested app' row is a little bit different than just a frequently used list. The drawer is trying to guess what apps you are using and make suggestions based on your usage. For instance, if you launch Waze every morning on your way to work, it is suppose to put Waze in there.... it'll show Netflix at night, etc.
Not sure how well that all works, but I do notice that the icons get changed up a bit now and then. But other than turning it on or off, I don't know of any other config.