Not every business that makes a fortune starts out with a groundbreaking idea. For every flashy startup focused on self-driving cars or sending people to the moon, there are hundreds of “boring” businesses making big money.

Here are four such businesses that have brought in a significant amount of cash, all of which simply built upon existing products or ideas.

Social Media Network — Farmers Business Network

Farmers Business Network (FBN) is a social media network that allows farmers to pool and compare data. The company also offers seeds to its members at discounted rates. Social media network is not necessarily a groundbreaking idea, nor is offering discounts to members. However, the company that can essentially be called Facebook for farmers raised $250 million in series F round, bringing its total funding close to $600 million.

Cartridges — Castle Ink

Lauren Elward, a high-school teacher, went through hundreds of ink cartridges printing out handouts and syllabi for her students, which led her to launch a recycling ink cartridge company, called Castle Ink, in a bid to go green and save money. Castle Ink made $1 million in annual sales in 2012, selling cartridges in the range of $10 to $30 (significantly cheaper than branded ones).

Razors — Dollar Shave Club

Another everyday product, razors, that has proven to be a highly profitable business is Dollar Shave Club — in 2016, the company was bought by Unilever for $1 billion. What started in March 2012 with a simple offering — high-quality but inexpensive razors — the company has since launched a lineup of additional products on its march toward owning the men's bathroom space.

Mattresses — Eve Sleep, Simba

Founded in 2014, UK-based online mattress retailer Eve Sleep started by selling only one mattress that it manufacturers itself, for about $535 for a single bed. Despite that, the company, which now also sells other sleep-related products such as pillows and sheets, listed on the London Stock Exchange in 2017, growing its revenue up 132 percent to £27.7 million ($37.21 million).

Another London-based online mattress company Simba, which operates in nine countries across Europe, North America and Asia, sells mattresses direct to consumers, and recently secured €21.5 million ($28.88 million) to fund its expansion plans.

It is OK to be Boring!

There’s so much focus on in terms of new technology like wearables, virtual reality (VR) and artificial intelligence (AI) these days, it can be easy to forget how valuable mundane, everyday items can be to our lives. These products hold the promise of bankable business opportunities.

Not every innovative idea is lucrative; in fact, businesses, whether small or large, that try to do something that nobody has done before often struggle. Take the example of Google Glass, the company’s first public attempt at wearable technology. The head-mounted computer looked like it came straight out of a sci-fi movie, but ultimately didn’t succeed.

Another such example of a failed product is Virtual Boy. Launched in 1995, it was Nintendo's take on virtual reality. The company sold less than one million units — the biggest hardware disappointment in Nintendo's history.

On the other hand, many startups that chose to stick with businesses in established and mundane industries have done quite well, as can be seen by the examples in this article. The bottom line is that whether you’ve come up with an earth-shattering new innovation or if you’re simply offering a product that everyone needs but isn’t futuristic, pursue it with vigor and ensure that you’re taking every step to succeed.