What android phones should you have for testing a simple 2D game?

I'm developing a 2d game that uses no special shaders or render pipeline. Just sprites and particle effects. So what should I be looking at as far as devices to have on hand for testing?

I've heard before that I should have a device that uses each major graphics card. Is it important to also have a device using the latest ~3 android versions?

Also, I already have a released game in the niche I'm publishing in, should I just be looking at top devices there? They are so spread out anyways that the most popular device is only 1% of the users.

 

The more real devices you have the better but obviously that is not always an option. Don't forget this can get expensive when you factor in iOS and tablets.

 

Unity has hardware stats on the most used devices for each platform.

Take a look at those stats, and perhaps get the low-end of those devices, and perhaps the mid to high end?

 

Was looking more for a strategy than the "just buy lots of devices" advice. Anyone with released products and a small team care to share their strategy for what android devices to have for in-house testing?