I assue you're asking about full splice with stacked veneers.
There are others but in my opinion there is no reason to look for others. They get cheaper than John's but they don't get any better - not for sale as a blank at least.
There are others. But certainly a Davis blank carries a big name with a lot of history behind it.
Every once in a while somebody pops up that most of us haven't even heard of before or heard very little of. In general they are compared to Davis splices...which says a lot. But there are definitely other options if one cares to look around. In the end, one might strongly consider a Davis blank....