The dates are listed in the rewards descriptions on the right--some rewards take a bit longer than others. But here's our current schedule; which is subject to change.
Generally, the first PDF extras go out in November and December, the playtest materials around the same time to playtester backers.
The Tome of Beasts print book and the related PDF are expected to ship in April for backers in the US. Outside the US, those rewards will take longer, likely arriving in May.
Special items such as the handbound leather edition and the Gen Con 2016 party won't happen until later still, in June and August respectively.