For reference:
My guess is we're finally getting the weapon clans/Outsiders War storyline. But there are tons of possibilities. The Bratva for example; Oliver and KGBeast clearly aren't on good terms anymore. But from what's been revealed of season 6 my guess was that Helix would be the main villains since Kreisberg said they'd be expanding on that storyline more next season. But given how Lyla's been acting, almost becoming the new Waller, I figured ARGUS might be the big bad next season too. It's hard to tell. We'll find out eventuallyOliver has finally solidified and strengthened his crime-fighting team only to have it threatened when unexpected enemies from his past return to Star City, forcing Oliver to rethink his relationship with each member of his “family”.