Smart ties are dark ties. That is a rule of thumb not hard to understand: a dark tie is less showy, more discreet, more serious.
It is also easier to wear a dark tie with an outfit. The Lawyer Background that I have described elsewhere on this site exists as it does because it is one of the few outfits with which one can effectively wear a bright tie.
Dark ties have had a particular popularity in the UK as a result of the club and military ties that predominated after the Second World War (and led to the growth of Jermyn Street as a source of colourful shirts to lie behind those ties).
But I would say that the dark tie is a staple in two situations. First, when the aim of your outfit is to be sober, simple and classic in your look (as many of Italian gentlemen featured on this column have been). And second, when you require a simple background that will not clash with an otherwise adventurous shirt/suit/coat. This is The Italian Background also mentioned previously on this site.
All this is by way of introduction to one suggestion: try purple or green as an alternative dark tie.
Navy blue would be the standard, followed by black and dark grey. I wear all three often. But I also have a particular penchant for (very dark) purple and (very dark) green as alternatives for a dark, smart tie.
Consider the illustrations. The Versace advert is an example of the first use of a dark tie – to complete a simple, classic outfit (a white shirt is essential here). Blue or grey would be the standard choice with that suit, but purple adds a subtle, whispered excitement.
The second illustration, this time a Paul Smith advert, shows someone wearing a simple tie and shirt in order to balance what is indisputably a loud suit. Again, the default setting would be navy, possibly grey or brown. But the purple tie adds a frisson of sophistication.
I would prefer a slightly darker shade, but that’s just me.
Dark green works just as well, and the first illustration shows a green tie providing an Italian-style background to a loudly striped suit. In fact, the green is so similar to navy you can hardly tell the difference. Almost silent excitement.
Finally, I recommend looking at these colours in woven ties, either wool or silk. Given that you are looking for darkness and depth of colour, a woven tie can be perfect.