For a girl, Diana, in honour of Prince Harry's mother, has been a favourite, as well as Elizabeth and Victoria.
Meanwhile, for a boy, Arthur is said to be at the top of the list.
However, it seems the Duke and Duchess of Sussex have gone for something completely different and unexpected - at least for now.
Taking to Instagram earlier this week, the duo revealed the sweet name they have been calling their unborn baby - and it may surprise you.
In a post thanking their supporters for donating funds to their preferred charities and organisations in lieu of sending gifts, Meghan and Harry referred to their little one as 'Baby Sussex.'
WATCH: Has Meghan and Harry had their baby in secret?
Meghan, who is currently 'nesting' at the couple's new Frogmore Cottage residence is expected to give birth any day now.
"Meghan has really been struck with the nesting impulse in the last few weeks," a source told The Sun, adding she's been lighting candles and keeping cosy.
"She loves the candles and the cottage smells divine."