Source: Taco Bell.

Breakfast is no longer about toast, scrambled eggs, and a side of bacon. There are plenty of restaurants shaking things up for a shot at getting your business in the morning.

Let's go over a few of the chains trying to raise the bar when it comes to the first meal of the day.

Taco Bell
Yum Brands' (NYSE:YUM) magnet for millennials took a bold breakfast menu nationwide last year. It turned heads with the now-discontinued Waffle Taco, but that unique item was replaced with the equally original Biscuit Taco.

Taco Bell also hasn't shied away from taking shots at niche leader McDonald's (NYSE:MCD) in its marketing. Taco Bell made a lot of noise in its rookie season folding up unconventional menu items. That's the right kind of momentum. 

Golden Corral
The privately held all-you-can-eat juggernaut doesn't want breakfast to end. Earlier this month, it kicked off a new campaign where many of its breakfast staples -- including pancakes, sausage, bacon, waffles -- are available all day. Even the made-to-order omelet station isn't taking lunch and dinner off. 

Traditionally, buffets had have powerful ways to cut costs and boost margins, but now Golden Corral is trying something new. The chain hired comedian Jeff Foxworthy to star in ads promoting the new breakfast offerings. The 500-unit chain expects the promotion to only last through the summer, but if it's popular, you know it's going to stick. 

Bojangles' (NASDAQ:BOJA) 
The recently public chain gets up earlier than its fried chicken rivals. Its menu of blueberry biscuits and chicken biscuit sandwiches has proven magnetic. In fact, Bojangles' recorded a whopping 38% of its revenue before 11 a.m. last year. 

Outside of Chick-fil-A, there isn't another chicken chain that has taken a big stand on breakfast. Given the recent popularity of chicken chains going public, it won't be a surprise if more of Bojangles' peers follow suit. 

Burger King
Golden Corral may be serving breakfast later in the day, but the country's second largest burger chain made waves last year by serving lunch earlier in the morning. Burger King -- now owned by Tim Horton's parent Restaurant Brands International (NYSE:QSR) -- moved to offer its iconic Whopper and other burgers at 5,000 of its restaurants as early as 8 a.m.

The move didn't resonate with consumers right away. Market watcher YouGov BrandIndex indicated that the move was actually hurting Burger King's brand buzz. It was still a bold move by a company that knows it has a lot of ground to make up if it wants to catch McDonald's. 

The country's largest restaurant chain in terms of number of outlets isn't McDonald's. Subway takes that honor, and this month, it will be five years since the sandwich chain dove head-first into the breakfast market. 

Subway's menu of egg, cheese, and meat sandwiches are served on toasted flatbread, but customers can also have them served on one of the chain's baked breads. One thing working against Subway is that most of its restaurants don't have drive-thru windows, denying it the chance to score hurried commuters who don't have time to get out to grab breakfast. However, it's still at it five years later, and now it may be a matter of time before other sub and sandwich shops follow suit.