There are 39 legal characters for OP. Plus 78 roles. Starter decks for all of them is not reasonable.
It's simple. If you don't have a deck, you have 7 options for quick pick up and play. If you want to play something else, get there early and buy a deck and put it together. Of course there will probably be user generated starter decks for all 39 characters in forums soon after OP starts.
This was kind of my idea. Have "quick-play" decks ready to go. If someone wants to customize when they are borrowing a deck at an event, have a couple of decks they can get to before the 2 hour time slot. I was in a session at Gencon that lost on time mainly because the first 25-35 minutes was consumed as newer players created their decks. Again, not a huge issue, but, sometimes too much choice is not good for new players.