Any high quality (Motorola, Blackberry, etc.) micro-usb charger will work. This is by electrical design. There is no need to list "working" micro-usb chargers as they all must work by definition (assuming they are not cheap crap from China).
All usb chargers are set at 5v and your computer's usb port will output at 500mA (1/2 amp) max. So using a micro-usb charger from 500mA and up will work fine. The phone will draw whatever current it needs to charge the batteries, so using a higher amp charger shouldn't be a problem since it simply won't draw all of that power. Think of it this way: Amps are pulled from the charger, not pushed to the phone. Voltages are pushed to the phone, not pulled from the charger. The OEM charger provides 5v (of course) at 1amp (1000mA). I'm also using chargers that provides 700mA and 850mA with no problems. Another person is using a 2amp Ipad charger with no problems as explained above.
Note: Using a charger with less than 1am (1000mA) will charge your phone a bit slower. However, if you just plug the phone in at night and go to sleep it will not matter as the phone will charge in a few hours anyway. If you need the FASTEST charge, find a charger that provides 1amp (this is what the HTC OEM charger provides). If you charge your phone by plugging it into your computer's usb port (500mA), then any charger 500mA up to 1amp will be faster.
I found these Blackberry chargers for only $4.50 Each on Amazon so I got 3!
It's a micro-usb charger that provides 5v (standard) at 700mA - works great.
http://www.amazon.com/gp/product/B001LRPN0S/ref=oss_product