The current sample of Title holders, and where named their Heirs Presumptive and Spares, comprised 212 peers of the top three ranks - 51 Dukes, 39 Marquess, 125 Earls.

Five 'regal' names revolve thoughout successive generations and are the first names of just shy of 60% of the sample. 

George - John - Charles - Henry - William 

Unsurprisingly in the era of the Hanoverian dynasty - George (20%) is dominant.

More interesting are the eyecatching names that are scattered throughout the peerage. The names shown here, with the exception of Other, are all family names that have made the shift to becoming first names:

Other - the preserve of the Earls of Plymouth (I have yet to determine whether or not this name is a spelling variation of Uther)

Wriothesley - initially the preserve of the Earls of Southampton (the family name of the 1st Earl was Writh or Wriothesley)

Heneage - entered the Finch family through the marriage of Moyle Finch to Elizabeth Heneage. James I elevated Elizabeth, nine years after the death of her Baronet husband, to Viscountess Maidstone and a further five years later Charles I elevated her to Countess of Winchilsea.

Clotworthy - the family name of the 1st Earl of Massereene, who died without issue; was the first name of the 1st Viscount Templetown.

Brownlow - a Lincolnshire and also an Anglo-Irish family name but also the first name of the 5th Duke of Ancaster. 

Vere - the Aubrey De Vere accompanied the Norman invasion and became tenant-in-chief to William I.