Time certainly flies when you're having fun -- and much fun was to be had this year, with all three major market indexes returning well more than 20% year to date even after the worst pullback in months by the market this past week.

To keep this joyous spirit going throughout the next two weeks leading up to Christmas, I've decided to once again count down this holiday season with my own Foolish rendition of the "12 Foolish Days of Christmas." Instead of turtle doves, French hens, and partridges invading pear trees, you'll be privy to high-growth stock ideas, game-changing innovations from a wealth of industries, unique ways to fuel your retirement account, and so on.

Over the previous four days of our Foolish holiday kickoff, we've counted down the:

Now it's time to move the countdown lower by a notch!

"On the 7th day of [Foolish] Christmas my true love gave to me ..."

Seven under-the-radar stocks that you could hold forever!
If you've been a reader or follower of The Motley Fool for years, or even a week, you're probably well aware that we like to look past the white noise that short-term gyrations cause and hold our stocks for the long-term so we can take advantage of compounding gains and dividends. We all know that this is simple when buying into well-known brands such as Coca-Cola or Procter & Gamble, or purchasing a staple energy stock such as ExxonMobil. But did you know there exists a universe of thousands of stocks beyond just these traditional few dozen staple names -- and that some offer just as much perceived security and wealth appreciation potential over the long run? Here are seven under-the-radar companies I believe you could sock away in your portfolio forever!

1. Silver Wheaton (WPM 2.23%)
"Hold a metals stock forever? Are you nuts?" Call me crazy like a fox, but if there is a metal and mining company that makes sense over the very long term, it'd be Silver Wheaton. Unlike your traditional miners, which spend copious amounts of money building out their mines, marketing their metals, and dealing with labor and administrative costs and repairs, Silver Wheaton does one thing and one thing only: buy royalty interests in mines at a fixed price.

Silver Wheaton provides cash upfront to miners looking to expand or develop a mine and in return gets an extremely low fixed cost on some portion (or all) of the metal being produced at that mine. For example, Silver Wheaton worked out a deal with HudBay Minerals in the summer of 2012 that secured it the right to purchase HudBay's silver at $5.90 an ounce, as well as all of its gold produced at the 777 mine through at least 2016 at just $400 an ounce. Silver Wheaton then pockets the difference as a profit.

With minimal overhead, a focus on long-term and life-of-mine contracts, and a dividend that's tied to the price of silver, unless metal prices fall back to 1995 levels this appears to be a great stock to hold forever.

2. International Game Technology (IGT -1.36%)
Casinos are certainly not one of my favorite long-term holds because of the highly competitive nature of the sector and high debt levels. Yet again, it's undeniable that in both good and bad economic times casinos usually perform well, as they attract guests looking to get away from reality for a few days at a time. Therefore, instead of focusing on the casinos themselves, I would suggest looking toward one of the largest casino-style game and software systems suppliers, International Game Technology, or IGT.

There are two primary reasons investors should consider IGT a forever type of investment. First, no matter how good or bad the economy is, casino-goers expect the latest in innovative games. This means casinos are in a constant tech-replacement cycle for their equipment, which lends IGT a steady stream of business. As further proof to that end, I'd point out that IGT has generated $188 million to $488 million in free cash flow every year for the past decade. 

Second, IGT also holds one of two online gaming licenses in the United States. Were online gaming to be legalized, it would be sitting in the driver's seat.

3. Quest Diagnostics (DGX -1.55%)
Recently, medical diagnostics companies have taken it on the chin as the prospect of reduced Medicare reimbursement rates and weaker government spending has reduced funding for some of their key customers, such as hospitals and universities that rely on government grants. But these are merely short-term drivers and pay little heed to the long-term growth potential of diagnostic plays like Quest Diagnostics.

The reason I'm particularly excited about this company over the next couple of decades lies with the potential for personalized diagnostics improving treatment potential. I firmly believe that genetic and other diagnostic testing that can be contracted out through Quest will help determine a best-course-of-action treatment for patients rather than physicians guessing as to how to treat a patient when multiple drug options are available.

In addition, the sheer number of biopharmaceutical clinical trials is growing. That's good news for Quest, which is contracted out to run some of these clinical and laboratory tests.

4. Bemis (BMS)
There are few companies that offer a more boring business model than Bemis, a manufacturer of flexible-packaging products and pressure-sensitive materials. The thing about "boring" though, is that boring often equates to steady cash flow regardless of how the economy is performing.

Bemis' product line includes everything from those annoying plastic capsules that are practically impossible to get into without scissors, a knife, and a little bit of luck, all the way to pressure-sensitive films used in decorative signs. Because of its diverse customer base, you'll rarely worry about Bemis' cash flow, and you certainly won't need to be concerned about its dividend, which has been raised for 30 consecutive years, placing it among an elite group of dividend aristocrats.

With its strong pricing power and the ability to make acquisitions as needed thanks to a prudent and fiscally responsible management team, I'd certainly suggest Bemis as a possible company to hold forever.

5. Hawaiian Electric Industries (NYSE: HE)
Finding a decent dividend in the utility sector isn't difficult, but finding a company you'd hold year in and year out isn't nearly as easy. Thankfully, mid-cap Hawaiian Electric Industries just might fit the bill.

The reason Hawaiian Electric makes for an attractive investment is the company's push into alternative energies, which cost more upfront but should set the company up for significantly lower costs than its peers over the long run. In addition to widely known alternative energy such as wind and solar, Hawaiian Electric has a facility that can run entirely on biofuels. If the company can utilize biofuels meaningfully moving forward, it could actually lower its costs even beyond alternative-energy giant NextEra Energy over the long run. 

The other exciting aspect of HEI is that it's a practical monopoly in Hawaii, controlling about 95% of the energy market. Little competition plus a product with steady demand in any economic environment means cash flow that investors can count on.

6. Global Payments (NYSE: GPN)
Everyone is probably familiar with payment-processing giants MasterCard and Visa, but few have ever heard of Global Payments, a payment-processing middleman between merchants and debit-card companies.

The reason I particularly like Global Payments is that without any loan liability, the company is free to profit off growing credit and debit-card usage, which is still largely untapped in many markets. Like MasterCard and Visa, Global Payments is angling its business to profit from the some 85% of global transactions still be conducted in cash. With easy-access financial tools like gift cards, Global Payments opens itself up to a wealth of consumers instead of just credit card payment processing.

7. PetSmart (PETM)
Finally, what smarter way to take advantage of Americans' acceptance of pets into our households than by purchasing pet-products retailer PetSmart for the long run?

According to the American Pet Products Association, since 1994 the amount Americans have spent on pet-related expenditures has more than tripled from $17 billion to an estimated $55.3 billion in 2013. Furthermore, the number of households that own a pet has increased notably from just 56% in 1988 to 68% in 2013.

PetSmart simply makes sense, because the vast majority of households consider a pet as part of the family, and not surprisingly, people will pay through the nose to make sure this family member stays healthy and has an ample selection of food and toys to choose from.