B6V

There is no B6V dagger standard

Lesh68 lists Bet Sex as its B6V standard. 

Garrison67 & Cowley69 uses 19 Tau as its B6V standard.

Gray01/03/06 lists one B6V star: HIP 109268 (=HD 209952, alf Gru), but all of
its other published types are B5V and B7IV. 

# No standard

Houk doesn't list a B6V pri. standard, but a secondary one (HD 45796).

MK43, Hiltner69, Cowley72, MK73, Garrison77, Garrison79, Keenan85, and
GrayAtlas do not list B6V standard.

Skiff08 did not flag any B6V stars as standards. 

Although Garrison77 does not list a B6V standard, they classify 3 stars as
B6V.  The brightest are HD 152909 (V=6.6; B6V) and HD 112999 (V=7.4;
B6V).

For 2 primary standards:
<B-V>(B6V) = -0.135 (+-0.003 sem, +-0.010 stdev; N=2 standards)
<U-B>(B6V) = -0.472 (+-0.013 sem, +-0.037 stdev; N=2 standards)

# Primary Standards
HD 90994 = 30 Sex = Bet Sex = HR 4119
  B6V: JM53,Jaschek64(most),Kennedy83(Lesh68(stan))
  B5: Cannon
  B5IV/V: Houk99
  Most recent classification is Lesh68
  V=5.071, B-V=-0.139, U=B=-0.504 (Mermilliod91) 
  QBV: (B-V)o=-0.142, (U-B)o=-0.499, E(B-V)= 0.003

HD 45796 = HR 2360 
  B6V: Jaschek78(Hiltner69),Houk(sec.standard),Houk75,Kennedy83(Hiltner69)
  B5: Cannon
  At least Hiltner69 & Houk agree on B6V type. 
  V=6.262, B-V=-0.141, U-B=-0.460 (Mermilliod 1991)
  QBV: (B-V)o=-0.128, (U-B)o=-0.446, E(B-V)=-0.013

# Weak Standard
HD 23338 = HR 1145 = 19 Tau = HIP 17531 = Taygeta (a Pleiad)
  B6V: JM53,Mendoza56,Cowley69(stan),Jaschek78(Herbig55)
  B6IV: Kennedy83(all),MK73,Lesh68
  B5: Cannon
  Skiff09 comments that Cannon18 uses Taygeta as B5 standard for HD types!
  Skiff09 lists no published types after MK73. 
  (B-V)o=-0.15, V=4.30 => Mv=-1.3. From my eye the Pleiades "turnoff" is at V=3.8.
  Taygete is the bluest MS B-star, just fainter than the terminal MS (but still "MS")
  But best considered "B6IV" due to MK73?