Just going to dump the ideas i have off.
SCP number: SCP-1244
SCP nickname: Universal stopwatch
Ingame mechanics: When used it would spin and start counting down from 60 seconds, when the counter reaches zero, a scripted event will occur, it could be multiple things selected at random.
-Sudden appearance of 173, 106 or some other hostile SCP.
-Some sort of scripted event.
(Warning!, big image!)
SCP number: SCP-1145
SCP nickname: Nagasaki teddy
Ingame mechanics: It could be found in it's containment cell, along with a switch to turn the lights on or off in a seperate room, if the player turns the lights off or maybe 079 could turn them off if the player remains in the room for too long, the bear will activate and begin pursuing the character, being too close to it or anything it has passed through will damage the player or make them ill, once it reaches the character they can pick it up the bear will damage them slightly less then if it was left alone, (It will still kill the player eventually, wearing the hazmat suit will stop the radiation from damaging the player for a short while until the radiation gets too powerful.
SCP number: SCP-640
SCP nickname: Lucent beam
Ingame mechanics: It could be found roaming the facility after a certain point (Possibly a scripted event to warn the player about it) if they attack, you take moderate damage and flinch making escape extremely difficult, the damage heals itself, but they are hard to escape once they begin attacking you, if you find there containment cell you can lure them in and if you shut the door on them, they become recontained and you won't find them in the facility anymore (Unless you open the door again).