After a stellar 2014, analyst estimates suggest Facebook (NASDAQ:FB) still has another 15% appreciation potential this year. That wouldn't match last year's run, but still nothing to sneeze at. However, we asked three of our Fool contributors for alternatives to Facebook that offer investor's even higher potential stock price growth in 2015. For various reasons, Apple (NASDAQ:AAPL), Google (NASDAQ:GOOG) (NASDAQ:GOOGL) and Tesla Motors (NASDAQ:TSLA) all made the cut.

Bob Ciura (AAPL): A 15% return from Facebook stock would be a nice return, but I believe investors can do even better with Apple. Apple is set to report quarterly earnings on Jan. 27, and if Apple beats, there's room for a strong rally. Analysts estimate Apple will earn $2.57 per share in the first fiscal quarter on $67.1 billion in revenue, which would represent 24% earnings growth and 16% revenue growth, year over year. Those are impressive growth figures, which of course is due largely to the release of the iPhone 6. The iPhone is Apple's flagship product, as it represents approximately 56% of Apple's revenue.

There's reason to be optimistic that Apple can reach its expectations. Apple sold more than 10 million iPhone 6 devices in the first weekend of availability. And, it's worth noting that number didn't even include sales in China, where the iPhone wasn't available until weeks later. China is a huge growth opportunity for Apple. In fact, China was Apple's fastest-growing geographic region in fiscal year 2014. Apple's China business is now a $30 billion business by annual revenue, which makes it the third-largest region for Apple behind only the Americas and Europe.

Plus, analytics firm Flurry found that 51% of all smartphones activated in the week before, and including Christmas, were iPhones.

If Apple can meet, or possibly exceed, expectations for the first quarter, there's room for the stock to rally. That's because Apple is still fairly cheap on a valuation basis. The stock trades for 16 times trailing earnings and 12 times 2015 profit estimates, which are actually lower multiples than the broader market. The market seems reluctant to bid up Apple stock, but if its first-quarter earnings beat expectations, a big rally may be in store.

Tim Brugger (Google): Even after its nearly 4% stock price hike this past week, Google is still down for the year, and that follows a disappointing 2014. There are several reasons for Google's poor share price performance, including hiccups with new products, negative sentiment, and declining cost-per-click, or CPC, ad rates. But the dark cloud over Google has overshadowed some recent successes, leaving its stock at value levels and substantial upside in 2015.

The king of innovation took one on the chin recently when it announced it was taking Google Glass off the market. While no one should expect every cutting-edge new technology like Glass to hit a homerun, the wearable flop added to the market's negativity. Though revenues jumped a whopping 20% last quarter, and will likely show continued growth in the soon-to-be-announced Q4, the 4% decline in CPC rates on Google sites stung.

The drop in CPC ad rates is largely due to online users shifting to mobile devices, which advertisers are loathe to pay the same rates as desktop spots. However, Google is in the midst of introducing a comprehensive suite of tools specifically for its mobile marketing partners that will help stem the rate slide, which ultimately will appease disgruntled shareholders.

Google's plans to dominate the fast-growing smart home market -- a business estimated to grow to $490 billion in the next five years -- are taking shape. Google's Nest smart thermostat is quickly becoming the hub from which all its smart devices will run, placing it firmly at the head of the smart home class. Yes, there have been some missteps in the past year or so. But with Google's depressed share price, coupled with new and potentially significant revenue drivers in place, matching Facebook's projected 15% growth in 2015 will be the tip of the iceberg.

Tamara Walsh (Tesla Motors): Electric-car maker Tesla Motors has been one of the best growth stories of the past five years. In fact, the stock is up more than 1,082% from its initial public offering price of just $17 in 2010. While this is undoubtedly impressive, investors could see even wilder upside in Tesla's stock during the next five years as the company moves ever closer to its mass market EV, the Gen 3.

The California-based company has serious momentum behind it heading into 2015 including the much-anticipated launch of its Crossover EV, Model X. Tesla now expects to begin Model X deliveries in the third-quarter of fiscal year 2015. Moreover, if the zero-emissions crossover is as "special" as Tesla's CEO Elon Musk proclaims, it could become Tesla's best-selling EV yet. And that's not the only growth catalyst Tesla has in its corner.

Tesla also kicked off the New Year with overwhelming demand for its new higher margin version of Model S. The company ended 2014 by introducing the world's first dual electric motor car, and Musk says, "Demand for the P85D is off the charts." This should significantly boost margins for Tesla going forward as the automaker now thinks more than 70% of the cars it produces this year will be dual-motor.

These catalysts as well as international expansion into new markets should electrify Tesla's stock in the quarters ahead.