Infact, how many different arriva liveries can you find?
Here's a little guide to their different liveries and trains:-

Firstly, a class 150 at York, in the blue and white arriva livery. (This is really still the regional railways livery but with different bading)
Next, is the 153 in arriva's green and cream with a yellow stripe shown above.
Arriva also operate trains in West Yorkshire, and these operate with a red 'metro' livery. Here is a class 155 in this livery:-

The train on the left that you can see in the next image is a class 156 in former Northern Spirit livery but badged as Arriva. Yet another different livery!

This picture was not taken on the Arriva network, but is amazingly still the livery carried on some 158 units operating under Arriva. In fact, I travelled on one just a few weeks ago.

The following 158 is under another arriva livery, this time the red metro. These are often also operated outside West Yorkshire too.

The last 158 is the livery normally seen on the arriva network. It is now operated on local services as well as the transpenninexpress network.

Now on to those terrible pacers! Here are 142s in newly badged regional railways livery and newer northern spirit green (these are now badged as arriva).

144s come in 3 different liveries; Former regional railwys livery (rebranded to Arriva), Old metro livery and new (flash!) metro livery.

Finally, arriva operate some electric trains. Firstly the 321 emus branded in metro livery...

...and the superb new 333s replacing the old pushdoor units (also shown).
Well in that little guide, I spotted 8 different liveries. What about you?
(PHEW!)