Note: did not mention the other "W" tablets since I do not have one. Your milage may vary.
These are things that I bought that work well with mine. YMMV. Keep in minds that I am of Scots heritage.
1) Acer case for W3 (fits in pocket) NP.BAG11.00A
2) Gear Head 7-Port USB 2.0 Hub for Mac (AC Power Adapter) (UH7250MAC)
3) Transcend 32GB MicroSDHC Class10 UHS-1 Memory Card with Adapter 45 MB/s (TS32GUSDU1E)
4) (W3) Afunta 8 inch Universal Tablet PC Leather Case with Keyboard/Holder/Capacitance Stylus for 8" PC (Micro USB keyboard) (W3 fits but not well, case is too tall, but if you need a portable keyboard...).
5) (W510) Tablet 10.2" Synthetic Leather Case with Keyboard and Stylus Pen for ePad and aPad (Black)
6) Plantronics .Audio 326 Stereo PC Headset
7) Micro HDMI to VGA Female Video Cable Cord Converter Adapter 1080P for PC Laptop Notebook Tablet DVD HDTV
8) BlueRigger High Speed Micro HDMI to HDMI cable with Ethernet (6 Feet)
9) Importer520 USB 2.0 Ethernet 10/100 Network LAN RJ45 Adapter
10) SANOXY USB 2.0 Female to Micro USB Male OTG On-The-Go Cable Adapter
11) EC TECHNOLOGY® Super Slim Mini Bluetooth 3.0 Wireless Keyboard (white)
ps I buy a lot from Amazon (plug)