I like #5, then #19...I think #18 could be cool if you remove the baseball shaped underscore and replace it with something similar to the underscore in #19. That to me has more of a sports feel.
Can you slightly edit #5 to make the yellow header look more like a flag? Perhaps extend the "t" in Stadium to look like a flag pole? Might look cool.
I like your designs best so far, thank you.
Charles