After the title screen, when Endou is running to the clubhouse, there are two signs. One, that I typeset, says "Soccer Club" - the other says "Recruiting members"
~3:30 - the comic says "Goro Goro", which is of course a pun on "Coro Coro" which has a lot of adverts for Inazuma.
"Soccer Frontier" - you can obviously hear "Football Frontier"... but remember, football everywhere in the world EXCEPT the United States = soccer. So it's actually "soccer frontier"... in a weird way.
When Endou gets into his room... he has a nice collection of books. Here they are:
Lower shelf, from left, "Futsa", "Soccer Bas", "Soccer Pa", "Soccer Physica", "Soccer in the World", "Soccer Rules"
Upper Shelf, From left, "Soccer, Road to Victory", "Soccer Tactics", "Soccer Pickles", "Soccer Frontier" , (Sideways)"Soccer", "Memories of Soccer" , "Soccer in the World", "Soccer Individual Practice Guide", "World Cup"