Honestly, I agree with many of the ones above but some of the ones mentioned may not agree with the wallet, I can add some cheaper ones that IME aren’t as aggressive as they say, the first one will most likely trigger some people.
Aussie Scott’s Fairy Wrasse (Cirrhilabrus scottorum)
If I’m telling you what is the truth then sure the Fiji and Cook variants can be aggressive to other fairy wrasse however, my Aussie Scott’s only chases my two male Lubbock’s every so often - There’s a ton of bickering between him and my Jade though because they’re both 4”. He will loose colour so I recommend just getting a female or transitional male because then you don’t buy a beautiful male just for it to become dull. Here’s a photo of mine (Note the flame red anal fin, the other two variants don’t have that).
Another one I have that could be a good fairy wrasse is the naoko fairy wrasse that is soon going to be moved into the tank with the Scott’s - Yes I have added a wrasse in with the Scott’s before, and he was established at that point. The naoko has the same colours as the Iridis just in a different pattern
I would take a photo of mine however, he has just tried to jump which makes me say he is getting too big for the nano tank.
Another two wrasses I have are both variants of Cirrhilabrus Lubbocki.
Both colour variants add a nice pop of purple and pink, I personally prefer the Indonesian variant (Although I do have both in the 4’ tank) both of my males get along with eachother.
Cebu Lubbock:
Indo Lubbock:
Another wrasse I have is the Iridis, be warned they are notoriously hard to ship - I have yet to have issues personally with it but the LFS I worked at has lost several of them because of it. After you get past the shipping stage it’s easy but trying to get one past that is easier said than done.
And the final wrasse I shall recommend is the Blue Star Leopard wrasse, yes they are hard to get eating but if she’s eating at the LFS and she doesn’t have any signs of illness or stress then it should be okay - Just make sure she has been in for Atleast a week. I would take a picture of my Blue star however she is asleep and I don’t want to stress out the naoko more than I already did trying to clean the glass.
Please excuse the bad iPhone pictures, I tried to get them as good as I could (I figured out a trick for a decent photo of the darty/quick swimmers)