In 2006, Bickford published an article
about where the current theories say we would find antiprotons and in what Lamont's. I've not finished the article but it claims Jupiter should be collecting kilograms worth of antimatter a year and that seturn should collect more than Jupiter. (Or so I understood.)
One of the really exciting things about having quantities of antimatter is that you can use it to produce and control a fission reaction in less-than-critical amounts of fission fuel. This may seem Luke no big deal or even a complete waist of antimatter but it promisses the possibility of currently impossible or very impractical engineering, such as making a refrigerator sized thorium breeder reactor that could power every aspect of your 100 year life from a basketball sized chunk of thorium; a material as common on Eartg as lead. (These numbers are being pulled from my behind on a late night so don't take them too seriously.)
The reason for this is that a heavy nucleus struck by an antiproton will force the nucleus to fission. The byproducts will be neutrons as usual to make other nucleus split. But, since it's not a critical mass, not enough of those neutrons will be captured on average to keep the reaction going. So the pile can't melt down.
But all those fission reactions will create more energy than there would have been if all the antiproton did was annihilate with a proton and by placing much of its annihilation energy onto fission fragments, the process makes it far easier to colllect that energy.
For near-term antimatter collection, I could see a company, launching with Space-X, put up a satellite that collected antiprotons around Earth in order to fuel a laboratory spaceship to travel to Saturn to collect the antimatter there.
In the star trek era, I could see a space station that used cosmic rays to produse large amounts of antimatter