Metroplex United has a pretty short history too. In the 60s, the teams in North Texas were numerous and difficult. In the Texas League, there were teams in Ft. Worth, Dallas, Arlington, and Frisco. They all had poor attendance and youth systems due to the teams pulling from the same pool. A businessman who graduated from Texas-Austin thought the best way to bring a top level soccer team to Dallas would be to merge the teams that already exist, to get a super team quick. United in 1965 under the name North Texas United, the team changed the name to Metroplex in 1974, their first season in the American Premier League, after a 2nd place League 2 finish the year before. They began filling up more and more of the Cotton Bowl after successful seasons in the top tier, the stadium they still use today. Metro was their strongest in the 80s. They won league titles in 1980, 81, and 86. US Open Titles in 81, and 85, then a CONCACAF title in 1987. After the passing of their owner in 1995, the team was sold to a wealthy oil baron who wanted to be the next Jerry Jones. The team got relegated in 1998, before the owner hired a GM who had soccer knowledge to turn the team over. Two seasons later, they were back up to the top league. They haven't won any trophies since the 80s, but their fanbase is huge. Typically, the supporters groups are split by their home town going by the names of the teams before the merger.
Metroplex has always had orange and white home uniforms. Traditionally, the clash uniform would be the color of the winner of the Cotton Bowl the winter before each season starts. They signed with Under Armour in 2011, who ended that tradition. They've had a lot of flag themed clashes, but this year they're representing the skyline.
So this was the 20th and final team in the APL. I may come back with League 2, but I'd really need some ideas before I go ahead with that.