#15 and #16 are both good, but I like #46 the most out of all your entries because it does a better job of showing movement from one object to the next with the arrows (like trading / swapping). I also like the font and size of the word in #46 better than your other 2 entries. The shadowing on your entry below the triangle of arrows is also a nice touch. Thanks for the entries!
#48 adds a nice touch to your #46. I like what you did with #49 making it a circle - can I see what it would look like if you put the graphic from #49 in as the letter 'o' ? Thank you!
Thank you for showing me these variations. The hexagon in #56 is a good idea, but a little too abstract for me to immediately see that it's arrows all pointing to each other.