Razer Naga Hex has seven side buttons that work perfectly for ESO abilities imo.
I have roll dodge bound to mouse wheel down, and weapon swap to mouse wheel up. My micro motor functions (aiming, ability casts, weapon swap, rolling) are on my right hand, and my macro motor functions (walking, sprinting, crouching, jumping, etc) are on my left hand, separating them across sides of my brain. This reduces reaction and processing times by a fraction of a second in the heat of combat. It also frees up my left hand to do nothing but move my character and pop potions -- no ability presses needed!
I highly recommend this setup.
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Alright, I may get a lot of hate for this but the one I use is the redragon 12 button mouse (think it's called the predition), I bought it at first because it was cheap and I didn't have a lot of money, but I've become hooked (Might not be the right word). I've tried to change several times to both the corsair and razer version but I've always gone back.