public class Client
{
    public Guid Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

var clientGenerator = Generator
    .For<Client>()
    .For(x => x.FirstName)
        .ChooseFrom(StaticData.FirstNames)
    .For(x => x.LastName)
        .ChooseRandomlyFrom(StaticData.LastNames)
    .For(x => x.Id)
        .CreateUsing(() => Guid.NewGuid());

var clients = clientGenerator.Generate(50).ToList();