I have been doing this and ya have to go to many diff retailers (online
) for the diff named (scify,comic,etc) I found that the specialty storefronts have alot. Be aware though with the name comes the price. I paid 40 a polyp for supermans and the avg price is around 25 a polyp for many of the others, i think i saw true yotas recently for 80ish for a 2-4 polyp frag. So to build a superhero tank is not going to be cheap bro. CMAC and trade shows are your best bet. I will have some nice frags in 6 or so months of what you are looking for. I will have some Hulk zoas in the next month or so when i frag my colony