I don't know if there's a definitive list, however you can see some of the special characters I've used in the past for ADX>FMT general parameters. You can also use the  , ® , and © in V11 and above from my understanding. It's best practice to use special characters within reason. 

At the solution and folder name the following is important to understand when it comes to special characters:

1) It is not possible to use an underscore or any special character such as dash, sharp or comma, for the Solution name and the folder name

2) The limit of the number of characters for a folder name is 10

3) There is no limit of the number of characters for Solution name but I can advise you to not exceed 12 characters.

I don't know if there's a definitive list, however you can see some of the special characters I've used in the past for ADX>FMT general parameters. You can also use the  , ® , and © in V11 and above from my understanding. It's best practice to use special characters within reason. 

At the solution and folder name the following is important to understand when it comes to special characters:

1) It is not possible to use an underscore or any special character such as dash, sharp or comma, for the Solution name and the folder name

2) The limit of the number of characters for a folder name is 10

3) There is no limit of the number of characters for Solution name but I can advise you to not exceed 12 characters.