You can find the main roster's mechanics here: www.deviantart.com/domobfdi/ar…
Potato: She will appear randomly during the night and will spawn one of the six in her roster. Unlike Dee Dee in the official UCN, she can't spawn someone from the main roster OR increase their difficulty. Also unlike Dee Dee, she will always spawn at least once per night.
Ghoulash: Weird grey gunk will fill the office. Click repeatedly on the gunk to get rid of it before it overfills. If it overfills the office, Ghoulash will form and attack you, ending your run.
Pilgrim Reaper: If she appear in the office, use the light switch to turn off the lights in the office to get rid of her. If you take too long, she will attack you, ending your run.
Anti Rattle: He'll approach from the left hallway and will instantly attack when he gets to your office instead of waiting for you to look at the cameras. Close the door when you hear his laugh, as he is about to stand next to the doorway. Unlike most of the others in Potato's Roster, he stays the rest of the night.
Mimic: She will spawn in the Treasure Chest room. This room is full of treasure chests of similar appearances. You must click on her to get rid of her. If you take too long, she'll charge into the office and attack you. The only way to tell which chest she is, you can barely see her arms on her sides.
Monitor: He will spawn in the office on your desk. Every now and then, he will turn on and show a few numbers. Press these numbers on your keyboard in the right order to turn him back off. If you take too long or make a mistake, he'll disable your camera and flashlight. He'll stay in your office until you get it right.
Shaker And Hannah: This duo will appear in the vents and crawl towards you. If Shaker gets in your office, she'll disable everything you have currently on for a short time, like the AC and camera. If Hannah gets in your office, she'll disable everything you have currently off for a short time, making it impossible to use them until they start working again.
Space: A clock appears in the office. Next to the clock is a sticky note that says a time and a camera number. When you hear the clock ring, stay away from that camera screen until the clock rings again. If you look at the camera at all during that time, Space will attack you instantly.
Metal Door: Don't worry, he is asleep. Just don't make too much noise around him. He'll leave later in the night if you don't bother him. If you make too much noise around him, he'll attack you.
Coal: She'll emit some smoke, which will agitate heat sensitive characters and blind you a short time. She's unavoidable.
XEP: She's similar to Potato, except she's more dangerous. Anyone that's in her roster will be spawned all together when she appears. She's similar to XOR in that form, and she's also similar to Dee Dee, as she rarely spawns in the office each night. It is possible to get both XEP and Potato in a night, but the chances are rather slim.
Slender Page: He'll teleport across camera screens. Don't stare at him too long, or he'll cause the cameras to static.
BETA Spyder: BETA Spyders swarm the office. Use the heater to scare them off. If they fill the room, then BETA Spyders will cause the lights to flicker and make a lot of screechy noises, annoying noise sensitive characters.
Power Prism: She will instantly make the office really bright and keep it like that. To turn off the brightness, go to the Power Box room and flip her switch off. This will get rid of the blinding light. The light also attracts the characters in the vents.
Triangle Block: He's rather passive. He'll just sit in your office and block a door way. This will prevent this door from closing, making you easy targets from hallway characters. Just flash your flashlight to get rid of him. It might take a few tries, however.
Polygon Block: He is quite rude. He'll snatch your flashlight and disable the doors for a short time. He'll also turn off the lights and increase the heat. Let him do his thing, however, cause if you try to use one of the things he disabled, he'll attack you.
Arrow Block: Similar to Beer, he can't decide if he wants to do mechanics of either Arcadey, Pilgrim Reaper, or Space. He will alternate every now and then each night. Which one he is doing, however, is difficult, since he's a little hard to spot due to his small size.