I sent a print pack of mine to a friend, but it will not show up in the addons list for him. It only works for me, and a couple friends on non steam Blockland.
I have:
Icons folder
Prints folder
Namecheck.txt
Description.txt
server.cs
Like I said before, it works for me, but not my friend. He uses Steam Blockland and I use non steam, along with my other friends.