You would think e-commerce and cloud computing giant Amazon.com (AMZN), after 20 years of unfettered growth, would have run out of room to pump up its top line. But the company continues to choose new opportunities. Amazon is willing to try its hand at almost sort of business, does well at the bulk of them - and threatens to destroy dozens of other companies with its success.

The latest foray into unfamiliar territory? The June acquisition of PillPack turns Amazon into a mail-order pharmacy, with a twist. PillPack packs all pills it dispenses into individual bags, each with a unique time and date to be consumed by the customer.

That's not Amazon's first venture outside its space. Amazon's also a grocer, a fashion venue, a peddler of handmade crafts and even a video game developer, just to name a few.

As a result, Amazon has become at best a headache, at worst a survival threat, for any rival organization in its past. Indeed, in November, we tallied up 32 companies that looked like potential victims of Amazon's never-ending expansion. Today, we're looking at 49 companies Amazon could kill - a few updates of the original list, but also an alarming number of new outfits that have fallen into Amazon's crosshairs - as well as one confirmed kill.

Advance Auto Parts, AutoZone, O'Reilly Automotive

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The unchecked growth of Amazon didn't faze auto parts suppliers like O'Reilly Automotive (ORLY), AutoZone (AZO) and Advance Auto Parts (AAP) for a long time. Car parts are too heavy, bulky and specialized to be handled like a consumer-centric commodity. And besides, when mechanics (DIYers or the real thing) need a part to use in a repair, they usually want it quickly. The big three names in the auto parts retailing game haven't needed to worry.

But times have changed, helped along by inventory-management technology and delivery networks that are willing and able to handle goods they simply couldn't before. That's why Amazon was willing to enter the fray in January 2017.

It didn't take long for brick-and-mortar operators to notice. AutoZone shares fell 27% during the first half of 2017, reflecting a first-quarter revenue and earnings miss. O'Reilly hit a similar headwind in Q2 2017 as well, as did Advance Auto Parts.

All three stocks have since recovered, as the market realizes Amazon hasn't yet unleashed the same havoc realizing Amazon hasn't unleashed the same kind of havoc on the auto parts retailing industry that it has on other consumer-facing markets. Give it time though. The fact that a little more than half of this trio's business, on average, comes from consumers rather than mechanics, it's a perfect opportunity for Amazon to become a disruptor.

Anderson's, Kroger, Walmart Grocery

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Amazon's purchase of Whole Foods Market sent shockwaves through the organic-grocery business, but just as vulnerable (albeit in a different way) are more conventional grocers such as Kroger (KR), privately owned Anderson's and the grocery arm of Walmart (WMT).

Yes, Whole Foods and Kroger somewhat overlap, particularly since Kroger has stepped up its organic and whole foods offering. But it's not the brick-and-mortar alternative that should worry Kroger shareholders the most. More concerning is that consumers are increasingly comfortable with the idea of ordering their potato chips, laundry detergent and ground coffee from Amazon.com, just like they order office supplies or books.

Recent numbers from industry research outfit One Click