I started seeing the left most icon on my screen a few days ago and I can't find a reference to what this image means. About a week earlier I upgraded my 2nd Gen Moto G to Lollipop.
Some techniques to find an image:
I recommend checking the official list of icons for Lollipop first. The icon depicts that the device is currently in vibration mode.
Other icons, as Jaskaranbir mentioned, in the order left to right, correspond to Network Wi-Fi, Signal Cellular full bar, and Battery partially filled with flash depicting charging.
If the official list isn't enough, do a reverse image search. Crop the icon and use it in a reverse image search engine (such as Google). See the example query.
At times, using your analysis of the icon in a web search also works.
When it comes to icons in right side of the status bar, it is safe to assume that the icon is part of SystemUI app, in which case, simply look into latter's drawables. Often, drawables have name that represents the logic behind the icon, so you can get a very good guess out of them.
For that Resource Browser can prove to be a very useful app. It can list all the drawables of an installed app in a single page, so you can view all of them easily.
(Click image to enlarge; image source: Google Play Store; no affiliation to app at all)
An alternative is to extract the APK in a folder, then run this command in that directory using a terminal emulator app
find ./ -type f -iname *.png -o -iname *.jpg -o -iname *.gif | while read line; do cp "$line" ./; done
You may need Busybox app installed. The command would recursively find all the images with PNG, JPG and GIF extension and copy them in the root of your directory. You can later see them using a file explorer app.