Options:
Random Mafia - exclude Mafioso. Reason - example of setup Mafioso, Mafioso, Random Mafia. Third one is often Mafioso.
Jester - lynch suicide ignores healing. Reason - if suicider is healed jester's death will be useless.
Mason Leader - can convert Survivors, can convert Jesters. Reason - sometimes when there are citizens people will scream to delete them.
Blackmailer - silenced won't be able to vote to lynch but will be able to vote innocent or guilty. Reason - "hey if ur silenced spam lynchvote".
Doctor - can't be healed. Reason - if there are 2 docs and they will heal themselves mafia alone won't be able to hurt them.
Other:
You can deduce the nick of the person you don't like depending on his model or hat because you can know how much points he has.
Roles:
Protector - Neutral - He wants random town member to survive.
Lawyer - Town - He will make his target impossible to be lynched next day. Probably limited uses.
Edit:
I added one new doc suggestion.