Am I...

[Sharkyland]

Hmm... I don't know about this, I guess I'm just picking the wrong cards. I keep getting rare canes than the other 'weapons'...

Canes > Guns > Swords > Slicers > Spears

[hypn0t1c]

The red pack gives a higher chance to get any type of item. As far as the different types of items, it's just random.

[Arislan]

Heres a guide on the boosters

http://www.pso-world.com/sections.php?op=viewarticle&artid=1525

This does mean that Black has a higher chance of Assists, but not because it boosts the rarity points on assist cards, but because it doesn't boost the rarity points on any other cards.