Well, technically, NLOP has the most freerolls. Now, if you are looking to build on a specific site, I have been having good luck with ACR. They have varied styles and they are every 3 hours, except for currently the 9 pm is a chance at a ticket into a $2 Venom tournament. CC has a freeroll on there, daily if you are platinum. There are also freerolls from other people on there, as well.