benefit
to gain benefit from

currency
to gain currency

entrance
...to gain entrance to... / to

foothold
to gain a foothold

gain
no gains without pains

gain on
to gain on a ship

gain over
convencer

gain upon
to gain on a ship

ground
to gain ground

hand
...to gain the upper hand / to get the upper hand / to have the upper hand

hearing
to gain a hearing

height
to gain height / to lose height

insight
to gain insight into

livelihood
.../ to gain one's livelihood

mastery
to gain the mastery

momentum
to gain momentum

offing
.../ to gain an offing / to secure an offing

pain
no pain no gain

pecuniary
for pecuniary gain

purpose
to gain one's purpose

weight
to gain weight