G5V 

HD 20630 is the G5V dagger type (Garrison94)

MK43 lists Mu Cas as their G5V standard.

Morgan65 lists Kap Cet (HD 20630) as the G5V standard, and classified
2 Hyads as G5V: HD 26756 & 28068.

Garrison72 used 16 Cyg B as their primary G5V standard. 

Corbally86 used the Hyad HD 26756 as their G5V standard. 

Skiff08 flags three stars as G5V standards, all from Keenan89: HD
20630 (G5V), HD 224930 (G5Vb Fe-2), HD 6582 (G5Vb).

Gray01/03/06 list 55 nearby G5V stars. Median HIP colors:
<B-V>(G5V) = 0.669 (+-0.005 sem, +-0.037 stdev; N=55)
<V-I>(G5V) = 0.728 (+-0.004 sem, +-0.030 stdev; N=55)


# Dagger standards
HD 20630 = kap Cet = kap^1 Cet = HR 996
  G5V: MK43,JM53,Morgan65,Keenan85,Keenan88,Keenan89,Garrison94,Keenan99,Houk,GrayAtlas

# Other standards
HD 6542 = mu Cas A = GJ 53A = HR 321
  G5Vb: MK43,Keenan88,Keenan99

HD 186427 = 16 Cyg B = HR 7504 = GJ 765.1B
  G5V: JM53,Garrison72(stan)

HD 26756 = Cl Melotte 25 17 = HIP 19781
  G5V: Corbally86(stan,Morgan65)

# Variants
HD 224930 = 85 Peg = HR 9088 
  G5Vb Fe-2: Keenan88