For pinch and supports, I always liked this style of trainer -

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That being said, I always get the best overall grip work from plain old thick bar work in the 2" - 2 1/2" range. Mostly the 2". Timed holds also worked well.
Never cared for grippers, they're neat for quick demonstrations, but my hands always felt too wrecked when using them in actual programming.
If I do buy another grip tool, it might be an anvil trainer just for fun -

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or maybe a climbing board -

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