Out of all the people in the DC Universe, the ones who were able to give Flash an important upgrade were his longtime enemies. When faced with a worst-case scenario, Barry Allen was able to overcome it in a way only a Rogue could.
While the Flash is the Fastest Man Alive, he has a crew of villains that specialize in tangling with speedsters. Led by Leonard Snart, aka Captain Cold, the Rogues are a group of blue-collar criminals that each possess unique technology that allows them to combat the Scarlet Speedster. Whether using the subzero power of Captain Cold's cold gun or Heat Wave's extremely powerful flamethrower, each Rogue has a trick up their sleeve to keep the Flash on his toes. They may not have powers, but they've been able to keep their small operation going no matter how many times the Flash puts them away. And it looks like all their confrontations have really helped teach the Flash a thing or two when the worst possible situation occurred.
In Flash #19 by Brian Buccellato, Francis Manapul, and Marcio Takara, Barry Allen has found himself on the wrong side of a prison break. To make matters worse, the Flash has lost his speed as a result of his abilities being drawn up by the mysterious H-Dial. With an armed crew determined to liberate the imprisoned Rogue Trickster, Barry has no choice but to fight back. In lieu of powers, he arms himself with equipment confiscated from the Rogues in years past. Using boomerangs, bombs, and the Weather Wizard's Weather Wand, Barry manages to hold his ground against the criminals. He even manages to quell the prison break using Captain Cold's gun, with a little assistance from a part-time hero named Turbo Charger.
Obviously, there’s never a good time for Flash to lose his speed, but the saving grace in this situation is Barry's adaptability. Weapons and gizmos might not be the Scarlet Speedster's forte, but he obviously knows how to use them when he's forced to get his hands dirty. In fact, the Flash just might have the Rogues to thank for teaching Barry how to survive after being robbed of his greatest asset.
Barry Allen is so used to his powers, he rarely has to consider a life without being able to run faster than the speed of light. But when that nightmare scenario presented itself, Flash had to consider how his villains the Rogues have had to manage for years. None of them have powers, but they're able to fight the Flash time and time again, sometimes successfully. By stepping in his enemies' shoes for a day, he saw what it was like to be at a disadvantage with nothing but thematic weapons. But all those times he faced off against Mirror Master and Captain Boomerang paid off and actually helped him resolve the situation non-lethally. The Rogues may not have intended it, but they showed the Flash he’s a capable hero whether he has his speed or not.