Just look to /vg/ server for role-specific traitor items. They have a bunch of really good ones.
http://ss13.moe/wiki/index.php/Syndicate_Items
Please remember that /vg/ only has traitors with 10 TC, so their item cost balance is a little different.
From what I remember:
Assistant:
-Pickpocket Gloves, a pair of black gloves that lets you strip people without producing messages. An item for the fanatically robust.
-Greytide Implant, a 20TC implant that when implanted into someone else, makes them a thrall to you. Mindshield provides no protection from the tide!
Engineer:
-Power Gloves, lets you shoot lightning when you stand on a powered wire! Looks like shock gloves, and damage is increased by power in the wire. If there's too much power, you get shocked as well...
Clown:
-Acid Banana Grenades, Grenades that, when armed, produce a number of banana peels that are both lubed and melt you when you remain on top of them.
-Clowns on /vg/ also have the clown car which can be emagged and upgraded with bananium coins and bananium, is also powered by banana juice.
-Eswords disguised as bananas. Yes, you can combine them into double banana eswords. Also a slippery item and can't be used by non-clowns...
Janitor:
-Proximity bombs disguised as floor signs.
Librarian:
-the E20, 4TC d20s that when thrown, explode! The size of the explosion is dependent on the result you roll! (a nat 20 ignores the bomb cap, a 1 gibs you instead!) Great for suicidal D&D games.
Botanist:
Ambrosia Cruciatus Seeds: It's space drugs except it's deadly.
Atmos Tech
-Weaponized flare launcher, shoots flares at lethal velocity as well as shotgun shells.
-Contortionist's Jumpsuit, Lets you ventcrawl but you only have ID slot and pockets as inventory space when you want to crawl.
Doctor/CMO:
Syndicate Wheelchair, a motorized wheelchair you can run people over with, like MULEbots.
Chemist/CMO:
Explosive Hug Chemical, A chemical that metabolizes slowly. As long as it's in someone's system, it causes them to explode when someone hugs them.
Miner:
-Master Trainer's Belt, a little background behind this one, /vg/ has buyable 'pokeballs' that let you store mobs friendly to you (lazarus injector on /vg/ revives mobs and makes them friendly, only to you). You can buy a belt that lets you store the pokeballs. This belt comes pre-loaded with 6 random hostile mobs (friendly to you), which include anything from space carp to syndicate commandos.
Chef:
Chef Excellence's Special Sauce, Poisonous condiment that kills in minutes. Apply directly to food.
Meat Cleaver, a cleaver that does esword damage, stuns on throw, and chops people into meat when they're dead.