I have been racking my brain trying to find out how people are creating their own decks by using boss cards since I only have the double-sided boss battle/boss power cards, and I see there is something called a Boss Pack. Did this come with the KickStarter, can it be purchased separately?
Yes, with the Kickstarter, there came a "boss pack" for each robot master, which included four copies each of 3 different cards themed to the particular boss. You could also buy more as add-ons during the campaign.
These are not available at retail, however, you may be able to find them on eBay or something.