Diodes

 1N3319B  Zener Diode, 50 watt, 20v

1N3996A - Zener Diode, 10w 5.1v MFR: NJS

Used in Heathkit SB220 and SB221

1N3996AR  Zener Diode, 10w 5.1v, Reverse Polarity, MFR: NJS

NTE5276AK  Zener Diode, 50 watt, 51v, MFR: NTE

Voltage - Zener (Nom) (Vz): 7.5 V
Tolerance: ±10%
Power - Max: 10 W

MFR: New Jersy Semiconductor
SKU: 1N2971A

1N4559B Solid State Inc. Zener Diode 50w 4.7v

MFR: Solid State, Inc.
SKU: 1N4559B

ESD Protection:  No
Maximum Operating Temperature: 175 °C
Maximum Power Dissipation: 50000 mW
Maximum Regulator Current: 470 mA
Maximum Reverse Leakage Current: 10 uA
Maximum Zener Impedance: 15 Ohm
Minimum Operating Temperature: -65 °C
Nominal Zener Voltage: 91 V
Type Voltage:  Regulator
Zener Voltage Tolerance: 5%

MFR: Solid State Incorporated
SKU: 1N2837B

1N3999A  Zener Diode 10 watt 6.8v
MFR: NJS
SKU: 1N3999A

Diode only. 
MFR: New Jersey Semi
SKU: 1N3303B

If you need mounting hardware, go to part #: 1N33-hard