Signing: TM responsible for putting up signs throughout the store. There are also early Sunday shifts TMs can pick up listed as Signing, which entails putting up the new 3"x3" sticky sales signs.
AP: Asset Protection TMs ensure that expensive merchandise has protective tags/spider wrap, monitor potential shrink, and apprehend. We have AP folks here who can tell you a lot more about it.
Electronics: similar to Hardlines, except that the Electronics TM holds the key to access protected items in their area. May also be responsible for zoning and reshop in areas of the store near Electronics (ASANTS).
Cash Office: I'm not sure what this entails but I'm pretty sure it's a workcenter. Something to do with money, I imagine.
Cart Attendant: They round up the carts and keep the front end looking brand.
Human Resources TM: They work on writing the schedule, handling personnel issues, hiring, orientation, etc. Not an area I'm too familiar with.
There are probably some workcenters I'm forgetting/not familiar with. If you check the Guides section of the Breakroom, you can find more information about various workcenters.