They hope to make big 'gains' in Congress in the coming election. [=they hope that many more members of their party will be elected to Congress]
Her hard work 'gained' her their respect. [=she has gained their respect through hard work; they respect her now because of her hard work]
a stock that was one of the year's biggest 'gainers' [=one of the stocks that increased the most in value]
(..) And since I'm the cool one, I'll have like two tanks sword fighting. I can't believe you. All your gifts all your powers, and you squander them for your own personal gain. - Yes! - NO! I 'm the villain, you're the good guy. I do something bad, and you come and get me. That's why I created you. (..)2010 Megamind
(..) You destroyed Metro Man. You took over the city and then you actually got me to care about you. Why are you so evil? Tricking me? What could you possibly hope to gain? Wait a minute. Oh, I don't believe this. Do you really think that I would ever be with you? No... (..)2010 Megamind