None exist yet - they'll show up next season.
They're CPU run teams that can only be played on by "legend" players - "legend" players being players who have finished their careers. Your current Vet has only so many games left (Flanders, for example, has 59 games to play at veteran still, unless you buy career boosts). Once you run out of vet games and career boosts, you have to either a) retire or b) go to the Legends leagues and play on, on a CPU team, in perpetuity.