Sentai Teams with Just Randomly Picked Rangers
Now for the just randomly picked rangers:
Flashmen- They were just kidnapped by Mess and were later rescued by the Flash people. Totally random. Thanks for pointing out ThatChick.
Livemen- Apparently out of random as they were the survivors who did the project themselves.
Jetmen- Unlike Ryu Tendo, the other four were accidentally bombarded by the birdonic waves. From the random four, only Gai Yuuki seemed to be destined for it.
Hurricangers- They were the last three available so they were selected.