F6V 

HD 30652 is the F6V dagger standard (Garrison 1994). 
HD 173667 and HD 142860 appear to be good standards too.

MK43,Morgan65, Morgan71, Garrison72, MorganAbt73,Cowley74, lists pi^3
Ori (HD 30652) as its F6V stnadard.

Cowley76 used pi^3 Ori (HD 30652) and 110 Her as their F6V standards. 

Skiff08 flags one stars as a F6V MK standard: pi^3 Ori = HD 30652 = HR 1543.

Morgan65 classified five F6V Hyads: HD 27483, 27534, 27848, 28406, 28483.

Gray01/03/06 classify 41 nearby stars as F6V. Their median HIP colors:
<B-V>(F6V) = 0.482 (+-0.003 sem, +-0.024 stdev; N=41)
<V-I>(F6V) = 0.557 (+-0.004 sem, +-0.024 stdev; N=41)

# No standard
Keenan85 & Corbally86 do not list a F6V standard

# dagger standard
HD 30652 = pi^3 Ori = 1 Ori = HIP 22449 = HR 1543 = GJ 178
  F6V: MK43,JM53,Morgan65,Morgan71,Garrison72(stan),MK73,MorganAbt73,Cowley74(stan),Gray89,Garrison94
  F6V-IV: Gray01
  No Houk type
  Morgan65 calls pi3 Ori the F6V "fundamental classification standard"
  B-V(HIP)=0.484, Vmag=3.19, Mv=3.67, dMv=-0.03, par=124.6+-0.9 mas

# Weak Standard
HD 142860 = gam Ser = HIP 78072 = HR 5933 = GJ 603
  F6V   : Jaschek78,Garcia89,JM53,Gray01,GrayNstars(only F6V stan),Houk(stan? not in catalog)
  F7VAB : Kennedy83
  F5    : Cannon
  B-V(HIP)=0.478, Vmag=3.85, Mv=3.62, dMv=-0.04, par=89.92+-0.83 mas

HD 173667 = 110 Her = HR 7061 = HIP 92043 = GJ 725.2 = GJ 9635
  F6V: JM53,Garcia89,Cowley76(stan),Jaschek78
  F5.5IV-V: Gray01 
  No Houk type
  B-V(HIP)=0.483, Vmag=4.19, Mv=2.79, dMv=-0.91, par=52.4+-0.6 mas
  slightly evolved? probably not a good dwarf standard

HD 170153 = chi Dra
  F6V: MK43,Roman52(lines strong)
  F7V: JM53,Cowley67,Jaschek64(most),Cowley76
  F7V mw: Gray01(metal weak)
  F8Vb: Barry70(uv metals vweak)
  fF8gF6mF6: Jaschek89
  F8: Cannon
  Morgan changed it from F6V (MK43) to F7V (JM53), then later it was considered
  a metal weak F7V or F8V. Probably not a useful standard. 

Note that these stars all have B-V ~ 0.48, but <Teff> varies by 200K !