Let's face it: catching all 700+ Pokemon is a hefty task for anyone to reasonably accomplish. But you know what they say: if you can't catch 'em, wear 'em!
They probably don't say that. But they should.
Anyways, look at this Pokemon-filled dress from Poprageous - while we cannot confirm EVERY Pokemon is present on this dress, the site seems to indicate that they're all there. Sadly, no Mega Evolutions are present. They must be saving that for the associated underpants.