The Morrigna and Hooded Spirits were the only two Trinity Gods I could find. TNN, Foromia, Mavereni, Eiru and MA/LA Man get access to both, while EA/MA/LA Ulm, MA/LA Marignon and MA Ys get access to only the Hooded Spirits.
They're definitely interesting though kinda unwieldy and full of exceptions and odd interactions. The Morrigna get -1 to their 'main' path and -2 to everything else. So a A4S4D4 on the design screen turns into a A3S2D2, A2S3D2, and A2S2D3. Extra paths are granted to all bodies of the Morrigna, though adding in anything less than 2 points in a magic path is completely pointless (except perhaps for path boosting) due to the innate -2 penalty. The Hooded Spirits are different. One body gets full Water and nothing else, one gets full Earth and nothing else, and the third gets full Nature and any additional paths. This means that Water/Earth, Nature/Earth, and (Earth or Water)/Anything crosspaths are not possible. So you could splash some Astral on to forge Moonvine bracelets but not Crystal Coins, since the Earth body won't get Astral.
Separating the Trinity gives them -2 to all paths which is almost crippling to the Morrigna, since they start out with some large penalties to begin with. At least the bless remains intact, so with some gear they could make good raiders in your domain. Keeping them together and casting some nasty Air, Astral or Death spells is probably a better use of them however, especially backed up by a communion. I'm not 100% certain how useful the Hooded Spirits are as combat casters, but at least they can react quickly to threats with their unify ability. Assuming you decide it's better to spread them out in peacetime instead of keeping them together for the extra research/dominion spread/whatever, of course.