Games here can be ... well. It's best to know the mod. Like Tricmagic ran a game with these roles:
Phantom Detective [Orange Thief]
Your clues on your father's killers have led you to a specific boat with a specific auction. The Venus Fluorite Necklace really does have mystical powers, but it is also a key to opening the way to a specific treasure. One the organization you're investigating wants access to. Undoubtedly they sent someone here to buy it, but with the help of a few magic tricks you've stolen and hidden it away. All you need to do is pin the blame and wait out the storm.
You win if you are the only Player remaining, or the remaining Player(s) cannot lynch or kill you.
Abilities
[1-Shot Day] Venusian Tougne: Tapping on the power of the amulet, you gain an additional vote during the next Day. Be wary, for this can give away the game to the observant. (This rumored property of the stone is known information to mafia, and can be suspected by town.)
[1-Shot Day] Sleight of Hand: Using your doves, you Frame 1 Player. They investigate as the Phantom Thief Role, and flip as such.
[0-Shot Day] The Empty Gun: Proof that you were the one to shoot the bullet. Though it has no fingerprints on it, it may still be useful.
Agent of the Malicious Agency of Fell Interstellar Agendas [Red Agent]
Some fool has chosen to steal the prize right from underneath your nose. It has the power to convince the weak-minded, and is key towards advancing an important plan you are not cleared to know. The Agency will not be pleased if you fail to retrieve it.
You win if all players are Eliminated, or unable to Lynch or Kill you. So long as the Thief of the Stone is caught.
[Auto] Noble Connections: Your connections to the MAFIA have you investigate as Town to any cops in the crowd. An upstanding member of society with no reason to steal the Venus Fluorite Necklace. You do, after all, have all the money.
[Day] Polite Donations: You "donate" some of your money to another Player, giving them a target and an additional action for the Day. They must use one action to target that player today, if possible. Alternatively, they can use this to refill one of their shots.
[Extra Action, Mafiakill, Day] My Personal Butler: Imp is Town. However, they are also your Butler. A handy scapegoat if needed. A useful ally if not. When you use this action, target a player. Your Butler will kill them in addition to their Action. This is not known to the Butler. Your Butler is unaware of your existence on the boat due to hypnosis performed upon them.
Noble Butler of the Butlers [Town Cleanser]
You are your employer's servant in all ways, and that includes making sure nothing untoward happens to them.
You win once all anti-town Players are Eliminated, via Lynch or Kill.
[Auto] The Butler Did It: You investigate as Mafia.
[Day] Light Hands, Idle Work: Target a Player. They cannot be killed today, but can be lynched. Any Frames the target is subjected to are cleansed, and status effects removed.
The Auctioneer [Town Tracker]
Stolen, from right under your nose. Who has ever heard of such a crime outside of shows? This was to be the crowning start to your career this year, and it's fumbled right off the starting line. Well, you will get to the bottom of this.
You win once all anti-town Players are Eliminated, via Lynch or Kill.
[Day] Tracking the Suspicious: You track yor target's actions today, learning who they visited and how many they used.
The Chef [Town Role Cop]
The Head Chef of thi little get together. It's your job to make sure the food is to everyone's tastes, make sure no food poisoning occurs, and that no allergy's are triggered. This also means you can talk with your fellow staff and find out who was on the guest list.
You win once all anti-town Players are Eliminated, via Lynch or Kill.
[Day] Talking up the Staff: You check the target's Role Name. Example, [The Chef].
The Security [Town Cop]
An old cop taking up the role of head of Security for this event. Your resume is long, and your skill in picking out the suspicious is on point. This theft would be a black mark on your company and likely result in a pay deduction. On top of the threat of a possible gunman.
You win once all anti-town Players are Eliminated, via Lynch or Kill.
[Day] Old Skills, New Task: You check the target's alignment.
The Author [Town Psychiatrist}
One might find a master psychiatrist a strange person to be on a boat bidding for a famous necklace, but they would not account for you having written a number of books on the human psyche. You skills in helping your patients is legendary, in the right circles. Who could have done it? That's what you wish to find out.
[Day] Frames of Mind: You check the target's mental state, determining if they are a Killer.
In a FBYOR, I think there's a chance that the game's well designed to capture the comprehended intent and preferences of the requesting player, and also to be balanced to be well playable by all. I'd be surprised if we have no investigators (plus we have some claims of that), but if we are without, then the game's designed to be played well without.