I don’t recall this Wesen myself, and I haven’t been able to find it anywhere other than the brief appearance of one in the journals in season 5, as you mentioned.
There are a few Wesen with tusks or horns, but none of them are mentioned as being hunted for them as far as I recall. There’s the Schinderdiv with large-ish tusks and the Fuilcre with large-ish horns. There’s also a unicorn-like Wesen called an Abath, with a single horn protruding from its forehead, but again…I don’t think this is the one you’re after.
At some point I plan to do a Grimm rewatch to finish the Grimm Stats and the glossary page. When I do I’ll be sure to keep a lookout!