Did you enjoy the whole bonus loot rotation from the Don't Fear the Reaper event? That's back. What about the St. Patrick's Day rewards? Yes, those too, with legendary recipes and the Luck of the Draw promotion (buy a hero and get another random hero for free, buy a costume and get another random costume for free). Winter holiday gifts, Lunar New Year gifts... it's an explosion of celebrations. If that's the sort of upgrade you like to see, you can check out the full list of repeats on the official announcement.
And if you're looking for a free random hero this weekend, apply the code RNDMHRO to your account. More free things!