Big Show and Yoko, Mark Henry isn't fat, he's buff so he doesn't count.
I realise where they're going and that WWE will push Roman Reigns straight to the top. However for me, Dean Ambrose is by far the most talented in that group and I think eventually if they just give him the spotlight then he's going to shine. As soon as he touches a mic everyone else can just sit down as he's magic on it. So It remains to be seen, I think they're all talented but to me Dean was the star of that group. I think Roman looks like the star of that group but I don't think he's nearly as talented as Dean.
The better term for fat than overweight is obese. Technically a wrestler like the Miz is probably overweight so that's my point.
As far as guys who just pop out to me as FAT and who I think overall is the best of all time I'd say Abdullah the Butcher, he had everything a legend is made of and has been around longer than almost every loyal wrestling fan these days has been alive.
Now overall a close second would be Big Van Vader who is probably the best in ring worker of any fat guy.