Here are my attempt on a Stax Earspeaker, amplifier and energizer units guide.
It is not complete, and might have errors. So please let me in if you have corrections, or additional products which I have not listed!

In production =
Bold Green
Out of production = Black
Earspeakers:Pro bias (5 pin plug)
:
- SR-007 (Omega II)
- 4070
- SR-404
- SR-303
- SR-202
- SR-003
- S-001 MK2 (proprietary plug)
- Lambda Nova Signature
- Lambda Nova Classic
- Lambda Nova
- SR-Omega
- Lambda Pro Classic
- SR-Lambda Signature
- SR-Lambda Pro
- SR-Sigma Pro
- SR-Gamma Pro
- Alfa Excellent
- SR-X/MK3 Pro
Non-Stax (works with an adapter cable):
- Koss ESP-950
- Sennheiser HE90
- Sennheiser HE60
Normal bias (6 pin plug)
:
- SR-Sigma
- SR-Lambda
- SR-X/MK3
- SR-5
- SR-X/MK2
- SR-X
- SR-3
Non-Stax (works with an adapter cable):
- Beyer ET1000 (180v bias, but work fine at 230v)
- Superex PEP-74
- Magnavox 1A9217
- Koss ESP6
- Koss ESP7
- Marantz SE-1
- Infinity ES-1
- Realistic HP-100
Special bias (
should work with an adapter cable)
:
- Jecklin Float (bias around 900v)
- Koss ESP9
- Koss ESP10
Amplifiers:Pro bias (5 pin connector)
:
- SRM-007tII
- SRM-727II
- SRM-006tII
- SRM-323II
- SRM-252II
- SRM-310
- SRM-001 (proprietary connector)
- SRM-007t
- SRM-717
- SRM-006t
- SRM-313
- SRM-212
- SRM-T2
- SRM-T1S
- SRM-T1
- SRM-T1W
- SRM-1/MK-2 PP
- SRM-1/MK2
- SRM-1 Pro
- SRA-14S
- SRM-X Pro
- SRM-Xh
- SRD-X Pro
Non-Stax (with Stax Pro connector):
- Singlepower ES-1
- HeadAmp Blue Hawaii Special Edition (coming soon-ish)
- HeadAmp KGSS
- Rudistor Egmont Signature HE90
- Rudistor Egmont Signature
- Rudistor Egmont
- McAlister Audio EA-6 (coming soon)
- McAlister Audio EA-4
- McAlister Audio EA-1
- Woo Audio GES
- Masters BA-215TM
- HeadAmp Aristaeus
- HeadAmp Blue Hawaii
Non-Stax (works with an adapter cable):
- Sennheiser HEV90
- Sennheiser HEV70
Normal bias (6 pin connector)
:
- SRM-007t (some)
- SRM-006t (some)
- SRM-313
- SRM-T2
- SRM-T1S
- SRM-1
- SRM-1/MK2
- SRM-1
- SRA-14S
- SRA-12S
- SRA-10S
Energizers:Pro bias (5 pin connector)
:
non-Stax (but have a Stax Pro connector):
Normal bias (6 pin connector)
:
- SRD-7 MK2
- SRD-7SB
- SRD-6SB
- SRD-7
- SRD-6
- SRD-5
As you probably notice, some of the amplifiers and energizers are listed in both "Pro" and "Normal".
Meaning that they have both connectors, and can drive any Stax electrostatic headspeaker.
Edit 1: Added more Stax Earspeakers, and sections for non-Stax headphones. Ref. 'spritzer'.
Edit 2: Added SRM-727II and SRM-717. As pointed out by 'Afrikane'.
Edit 3: List sorted in chronological order, and added
Green colour coding to the current in-production models.
Edit 4: Added non-Stax amplifiers and energizers.
Edit 5: Its Superex, not Suprex. Ref. 'wualta'.
Edit 6: Added
Master BA-215TM.