Here are the pictures of my older Snap-on quick change style snap ring pliers. They are the same thickness and size as the quick change knob style but mine have the knurled thumbscrew. They are still rather quick to change but I would prefer to have the quick change knob.
The full set has straight, 45-degree and 90-degree in four pin sizes.
I have several pair of the transmission style of flat retainer ring pliers. These vary from Snap-on, Cornwell and Proto but I really like the Snap-on ones.
Close-up of the Snap-on retainer ring pliers to show the thickness of the body.
And I had forgotten I do have an old pair of the Knipex in a very small size. I remember I had to purchase these for a specific hydraulic pump that my others wouldn't reach in to but that was many years ago.
I asked my co-worker yesterday afternoon about how he liked his Knipex retaining ring pliers and all he said was "they do the job". That's all I could get out of him.