Just make your own. Put oatmeal and flax seed oil into a blender, some peanut butter, in milk, add some protein powder, and wampum!
Most weight gainers I know have way too much sodium (which accounts for their weight gaining propensities)
Oatmeal, flax, coconut/olive oil, milk/heavy cream, bananas, peanut butter, and any combination thereof are good choices for weight-gainer additives.
And yes, many commercial weight-gain products are extremely high in sodium and also SUGAR.
Then again, that's why most of them taste so good.
+1 for making your own.