Well I found an article that says a lot:
https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades
And from that I pulled what I think I need that is Relevant:
Generation 1:
Late 2010 and Mid 2011
MacBook Air 11″ (Model A1370)
MacBook Air 13″ (Model A1369)
mSATA III interface
6+12 Pin connector
Generation 2:
MacBook Pro (Mid 2012 - Early 2013)
iMac (Late 2012 - Early 2013)
MacBook Air (Mid 2012)
Mid 2012
MacBook Air 11″ (model A1465)
MacBook Air 13″ (model A1466)
Gen. 2A: (shorter, wider)
Gen. 2B: (taller, thinner)
mSATA III interface
7+17 Pin connector
Generation 3
Mid 2013 through Mid 2015
(Not MacBook Air and iMac 21.5″)
MacBook Air (Mid 2013 - Early 2014)
Can upgrade to Generation 4 Drive?
Mac Pro (Late 2013)
(Have heatsinks attached with strong thermally conductive adhesive.)
New MacBook Pro
Require macOS 10.10.3 or later
supports NVMe SSD
Can upgrade to Generation 5 Drive?
MacBook Pro (Late 2013 - Mid 2014)
Require macOS 10.10.3 or later
iMac (Late 2013 - Late 2015)
Can upgrade to Generation 4 Drive?
Gen. 3A: (128GB,256bGB,512GB)
PCIe 2.0 x2 interface
Gen. 3B: (1TB, 2x Wider)
PCIe 2.0 x4 interface
12+16 Pin connector
use AHCI technology
Mac mini (Late 2014)
flex cable with 12+16 pin female connector on one side
female 40 pin mezzanine connector which attaches to the
40 pin male connector on the motherboard.
Generation 4
MacBook Air (Early 2015 - Mid 2017)
Cannot fit 4B Drive (1TB)
MacBook Pro (Early 2015 - Mid 2015)
Can upgrade to Generation 5 Drive?
iMac (Late 2015)
Gen. 4A: (128GB,256bGB,512GB)
Gen. 4B: (1TB)
MacBook Air 11″ Gen. 4C: PCIe 2.0 x2 interface
PCIe 3.0 x4 interface
12+16 Pin connector
Generation 5
MacBook Pro (Late 2016 - Mid 2017)
Gen. 5A: 22+34 Pin connector
Gen. 5B: 12+16 Pin connector
NVMe protocol
PCIe 3.0 x4 interface
12+16 Pin connector: Gen. 5B
22+34 Pin connector: Gen. 5A
I guess the different types would be clarified through the Connectors used on the SSD's.
I needed this list so I could order different Adapters to pull data from Apple hard drives for data recovery at my shop. But needed to know which adapters I needed to order. I hope this list helps others wanting to know the same thing.
Adapter types:
Generation 1: 6+12 Pin connector
Generation 2: 7+17 Pin connector
Generation 3 4 5a: 12+16 Pin connector
Generation 5b: 22+34 Pin connector