I'm counting about 15 different cores since 900G and AMF started putting out equipment.
Quite a few of those cores are used in 1 or 2 balls (ie: Solid and Pearl versions) and then we see something new.
Examples:
Maniac: one release
Lunatic: one release
Long Shot & Favorite: solid & pearl
Profit: solid & pearl
Bank: solid & pearl
Link: single release in multiple colors
Missing Link: single release in multiple colors
Bounty: Bounty and then Bounty Hunters (solid and pearl)
Clutch: solid and pearl
Double Clutch: solid and pearl
Hype: multiple colors, and urethane
The only cores that we've seen used multiple times are the Break core (s70, pearl, s75, Break Out, The Eagle) - and also modified version in the Break Point line (solid and pearl) - and the "Code" core that we've seen in the Code and modified versions in the N'Code, Sideways, and "Mega" line.
Many people knock the other companies for reusing the same core designs for an extended period of time. Even though they are a smaller company, it just seems like 900G is constantly creating new stuff.....yet you never hear anybody give them credit for it.
Will we continue to see new core designs with each new release, or at some point will we see some of the older cores reintroduced? If not, is there a reason?