Dividend growth stocks can make for attractive investments because the recurring income you receive has the potential to rise every year. But dividends are discretionary, and even if there is an increase, it may just be a nominal $0.02 hike -- especially if a company just wants to keep a streak going.

A couple of stocks that aren't Dividend Aristocrats but have still been generous with making dividend hikes are Humana (HUM 0.42%) and FedEx (FDX 0.11%). In just three years, they've increased their payouts by more than 40%. 

1. Humana

Health insurance company Humana makes for a safe, steady investment to buy and hold. The nature of its business makes it a good pillar to build a portfolio around, as health insurance is always needed.

Its business generates small-but-consistent profits. Last year, the company's net income totaled $2.9 billion and was 3.5% of its top line ($83 billion). The year before that, even as COVID-19 was weighing down the healthcare system, Humana's profits were a solid 4.4% of revenue.

Over the past four quarters, the company's free cash flow has been more than $2 billion, easily enough to cover the $362 million in cash dividends it paid out during that time. That leaves plenty of room for Humana to make more hikes to its dividend, which today yields a relatively modest 0.65% (the S&P 500 average is around 1.7%).

That gap could shrink, as Humana has been aggressive in boosting its payouts. Its current quarterly payment of $0.7875 is 43% higher than the $0.55 that it was paying shareholders just three years ago. That averages out to a compounded annual growth rate of 12.7%. Humana doesn't have a long track record for consecutive dividend increases -- this year's increase was the sixth straight -- but there's plenty of potential for the yield to get larger in the years ahead.

The healthcare stock has proven to be a reliable investment, and its shares are up 5% year to date, outperforming the S&P 500, which is down 20%.

2. FedEx

Logistics company FedEx is more of your typical growth stock. It makes for an appealing investment because growth in e-commerce and the general economy should result in more packages being shipped around the world, leading to strong growth for its business.

FedEx is coming off another strong year in fiscal 2022, as sales of $24.4 billion for the period ending May 31 grew at a rate of 8% year over year. Adjusted per-share profits of $6.87 were also better than the $5.01 that it reported a year earlier.

Before the release of the year-end numbers, the company announced an incredibly generous dividend increase of 53%, boosting the quarterly dividend from $0.75 to $1.15. A year earlier, the company raised its payouts by 15.4%, and prior to that, the last rate hike was in 2018. FedEx doesn't have an impressive dividend streak going, but that shouldn't bother income investors.

Streaks can be kept going by nominal $0.01 increases that offer negligible growth for income investors. And by FedEx not having a long streak, there's less pressure on the company to keep raising its payouts. Technically, its dividend has risen by 77% in three years, but those rate hikes only took place in the past two years.

FedEx may never end up being a Dividend Aristocrat, and that shouldn't deter investors from buying the stock. It's more important that the business is growing and providing a solid, growing dividend, regardless of whether it follows a schedule or not.

Shares of FedEx are down 15% this year. This could be a strong underrated dividend growth stock to buy today.