I compiled a spreadsheet of brands I could find and what they offered.
Interesting to see who chose what.
Cornwell is the only one to offer an extra short 3/8 6pt chrome.
Snap-on includes a FDX semi-deep in both of their kits.*
(They seem to be the only one that includes any type of modified profile socket.)
(*Snap-on is the only brand that breaks these into two separate sets, one for 1/4 drive only and the other 3/8 drive only.)
Diehard seems to be the only one to include a 10mm hex bit socket.
Snap-on, Matco, and Cornwell are the only ones that include 1/4 and 3/8 impact swivels, with Snap-on also including a 3/8 deep swivel.
(SK included a 3/8 swivel but that's a moot point now.)
Snap-on only includes a 3/8 deep chrome universal.
Pittsburgh (and SK) are the only ones that include 1/2 drive.
Snap-on (and SK) include 12 point 1/4 shallow.
Husky (and SK) include 12 point 3/8 shallow. (SK had 12 point 3/8 deep as well.)
Titan and Platinum-tech are the only ones that include 12pt 3/8 chrome universals. Everyone else is 6pt.
Matco and Cornwell include shallow and deep 1/4 magnetic sockets. CTA includes 1/4 and 3/8 magnetic shallow only.
Laser includes a very unique fixed flare socket and flex flare crowsfoot socket. Pretty cool.
Laser and PowerTorque include 3/8 extra deep.
VIM exclusively includes 1/4 extra deep, a 1/4 6pt spring loaded universal joint with external hex base (Dual Drive), and 1/4 shallow (Dual Drive) socket.
Astro has a proprietary glow feature, that aids in finding lost sockets, but is limited to a 4 pc set.
Other brands (not mentioned above) that dont offer anything out of the ordinary include Carlyle, Gearwrench, Duralast, OEM Tools and Powerbuilt.
If I missed any brands (no generic), let me know and I will update my spreadsheet.