B2V

There are no B2V dagger standards, but Bet^2 Sco (HD 144218) probably best.

Garcia89 lists 8 B2V standards: HD 3901, 4180, 144218, 147934, 148605,
191746, 208947, 218440

Lesh68 lists 22 Sco & 51 Cyg as their primary B2V standards, with
HD 36430 & HD 43955 as secondary B2V standards.  

Walborn71 & Walborn90 adopts HD 42401 as their B2V standard.

Hiltner69 & Garrison77 list HD 148605 (22 Sco) as their B2V standard

Cowley72 adopted Sig Sgr as their B2V standard. 

Garrison79 lists 22 Sco, 13 Sco, and Bet Sco B (IV-V) as their B2V standards.

Skiff08 lists 6 stars as B2V standards (and variants): HD 148605 (B2V;
MK73), HD 175191 (B2V; MK73), HD 120324 (B2V:e; MK78), HD 144218 (B2V;
MK78), HD 36485 (B2Vh; MK78), HD 37017 (B2Vh; MK78).

Median Mermilliod91 colors among the 4 standards:
<B-V>(B2V) = -0.212 (N=4 standards)
<U-B>(B2V) = -0.777 (N=4 standards)

# Primary Standards
HD 144218 = bet^2 Sco = 8 Sco B = HR 5985
  B2V: JM53,Bertiau58,Slettebak63,Levato75,MK78,Abt81,Gahm83,Keenan85,Garcia89,Houk
  B2IV-V: Lesh68,Garrison79(stan)
  B2IV/V: Garrison67
  B3V: Morris61
  Jaschek64: majority say B2V, with one B3V
  M91: V=4.903+-0.014, B-V=-0.024+-0.008, U-B=-0.690+-0.014
  =>QBV=> (B-V)o=-0.221, (U-B)o=-0.813, E(B-V)= 0.197, T=21192.

# Secondary Standard
HD 148605 = 22 Sco = HR 6141
  B2V: Houk,Jaschek64(all),Thacheray67(B2Vn),Lesh68(stan),Slettebak68,Hiltner69(stan),MK73,Garrison77(stan),Jaschek78(Garrison67),Garrison79(stan),Kennedy83(all),GrayAtlas
  B2.5V: Walborn90
  B3V: Houk88
  B3: Cannon
  M91: V=4.782+-0.007, B-V=-0.125+-0.020, U-B=-0.728+-0.026
  =>QBV=> (B-V)o=-0.211, (U-B)o=-0.772, E(B-V)= 0.086, T=20084.
  Mostly B2V, but Walborn90 calls B2.5V

HD 42401:
  B2V: Kennedy83(Walborn71),Walborn90
  B5: Cannon
  No other classifications! But a Walborn90 B2V standard, so good enough.
  M91: V=7.442+-0.073, B-V=-0.042+-0.015, U-B=-0.620+-?
  =>QBV=> (B-V)o=-0.196, (U-B)o=-0.716, E(B-V)= 0.154, T=18682.
 
HD 145482 = HR 6028 = 13 Sco
  B2V: Jaschek78(Garrison67),Slettebak68,Hiltner69,Garrison79(stan),Houk82(Garrison)
  B2.5Vn: Bertiau58
  B3Vn: deVaucoleur57
  B3: Cannon
  Jaschek64 shows 5 different types published for 13 Sco (B2/3V/Vn). 

# Weak Standards
HD 191746 = HIP 99400
  B2V: JM53,Garcia89
  B2IV: Jaschek78(Guetter68),Kennedy83(Guetter68)
  B2III/IV: Claussen79
  B3: Cannon
  Good agreement on B2 temperature type, but only JM53 calls dwarf
  Mediocre standard
  M91: V=7.170+-?, B-V=0.010+-?, U-B=-0.670+-?
  =>QBV=> (B-V)o=-0.222, (U-B)o=-0.818, E(B-V)= 0.232, T=21342.

HD 218440 = HR 8803
  B2V: JM53,Guetter68,Garcia89
  B2.5IV: Jaschek78(Lesh68)
  Spectroscopic binary, mediocre standard
  M91: V=6.391+-0.010, B-V=-0.011+-0.010, U-B=-0.636+-0.005
  =>QBV=> (B-V)o=-0.208, (U-B)o=-0.761, E(B-V)= 0.197, T=19783.

HD 3901 = ksi Cas = 19 Cas = HR 179
  B2V: JM53,Garcia89,Hoffleit91
  B2.5V: Jaschek78(Lesh68),Kennedy83
  B3: Cannon
  Jaschek64: vast majority list B2V (one B3IV)
  Basically the only two good classifications are JM53 and Lesh68

HD 208947 = HR 8384
  B2V: JM53,Lesh68,Garcia89
  B3V: Abt84,Ahmad52
  B3: Cannon,Petrie67(B3+B3)
  I'll adopt the Morgan & Lesh B2V type, but probably a mediocre standard
  M91: V=6.430+-0.030, B-V=-0.055+-0.005, U-B=-0.685+-0.005
  =>QBV=> (B-V)o=-0.213, (U-B)o=-0.781, E(B-V)= 0.158, T=20313.

HD 147933 = rho Oph
  B2V: MK43,Bertiau58,Hiltner69,Abt83,Abt86,Garcia89
  B2IV/V: Murphy69
  B2IV+B2V: Garrison67,Racine68
  B2/3V: Houk88 
  B3IV: Morris61
  B1.5V: Buscombe69
  B5: Cannon
  Jaschek64 lists B2V,B3IV, and B5N: 
  ~3" binary
  Probably not the best standard as it is tight binary
  M91(combined): V=4.600+-0.016, B-V=0.230+-0.007, U-B=-0.568+-0.011
  #=>QBV=> (B-V)o=-0.239, (U-B)o=-0.884, E(B-V)= 0.469, T=23363.

HD 3360 = zet Cas = 17 Cas = HR 153
  B2V: Ahmad52,JM53
  B2IV: MK43,Underhill57,MK73,Lesh68,Jaschek78(Lesh68),Garcia89,Hoffleit91
  B3: Cannon
  Jaschek64 shows mostly B2V with a few B2IV and B2.5IV
  From Johnson66 data, I estimate (B-V)o=-0.244, E(B-V)=0.054
  The concensus and MK73 suggest B2IV - no doubt about temperature type (B2)

HD 11529 = ome Cas = 46 Cas = HR 548
  B2V: JM53
  B8III: Jaschek78(Cowley72),Molnar72
  B7III: Garrison94
  B8: Cannon
  Did I mis-type this number? Clearly not a B2V

HD 35468 = gam Ori 
  B2V: MK43
  B2III: Morgan55,Lesh68,MK73,Jaschek78(M55),Garcia89,Walborn90
  B2: Cannon
  Jaschek64: split of B2III and B2IV
  Gam Ori was "the" B2V standard in MK43. 
  So this star turned from B2V => B2III and stuck. Not a dwarf.

HD 175191 = sig Sgr = HR 7121
  B2.5V: MK73,Garrison79(stan),Houk82
  B2V: Cowley72(stan)
  B3IV: Hiltner69
  B3: Cannon
  B4IV: Buscombe60,Morris61,Buscombe69
  Jaschek64 shows B3IV-V,B3V,B4IV,B4V
  Not very good agreement between authors. 

HD 120324 = HR 5193 = mu Cen
  B2V:e: MK78
  B2Vnep: Levenhagen06,Bertiau58(B2V:nep)
  B2IV-Ve: Houk78(Hiltner69),Slettebak82
  B2p: Cannon
  B2: Mendoza58
  B3Ve: deVaucouleurs57
  MK78 shows this as a prototypical Be star classified as "B2V:e"
  Jaschek64 lists 5 different classifications, but all B2-B3Ve
  UCL Member. Could be considered a "B2Ve" standard? 

HD 36485 = del Ori C (companion ("ft")) = HR 1851 B?
  B2V: Morgan55,Murphy69,MK78(B2Vh),Houk99(Warren)
  B2IV-V: Lesh68
  B2.5V: Levato75
  B3V: Berger58
  B4IV: Abt83
  B6: Wilson50
  "h" is helium? V=6.9 star 52" North comp to V=2.5 O9 star HD 36486. 
  Some dispersion in the published types. 

HD 37017 = HR 1890 
  B2V: Morgan52,MK78(B2Vh),Levato75,
  B2IV: Schild71
  B1.5V: Sharpless52,Jaschek78(Lesh68),Abt77(B1.5Vp)
  B0: Cannon
  B2/3V: Houk99(q=3)
  He strong according to Abt77 & 1996VA......8...83M
  Types vary a bit in the literature, probably lousy standard. 

HD 197511 = 51 Cyg =
  B2V: Slettebak55,Jaschek64(one),Jaschek78(Lesh68(stan))
  B3: Cannon
  Only Lesh68 considered this a standard, but otherwise OK. 

HD 36430 = Parenago 679 = ALS 16198
  B2V: Sharpless52,Jaschek64(all),Lesh68(sec.stan))
  B2.5Vsn: Abt77
  B3V: Houk99(q=1)
  B3: Cannon
  Only Lesh68 considered this a standard, but Abt & Houk say >B2V.

HD 43955 = HR 2266
  B2V: Slettebak55,Jaschek64(one),Jaschek78(Lesh68(sec.stan))
  B2/3V: Houk88
  B3: Cannon
  Only Lesh68 considered this a standard, but otherwise OK. 

HD 37129 = Parenago 2314 = SAO 132345
  B2V: Jaschek64(only; "B2Vp"),Abt68,Jaschek78(Sharpless52;"B2Vp")
  B2.5Vsn: AbtLevato77
  B3III/IV: Houk99
  B5: Cannon
  Abt68's B2V standard, but called "B2.5Vsn" in Abt77. vsini=65 km/s (Houk).
  Insufficient agreement and use to be considered a standard. 

# Other
Kap Cen
  B2V: Garrison96

Alf Ara
  B2Vne: Garrison96