Vigilance
Explorer
Incorrect! They actually boosted one company in the Monster Manual II.
Being able to find three examples in ten years sort of proves my point (I'm calling MMII, Unearthed Arcana, and Call of Cthulhu d20 as examples).
They were not interested in highlighting 3PP's. Which is fine, I don't blame them for that. It's just a fact.
Yes, there were occasional experiments, such as Unearthed Arcana.
But there was never any sort of concerted effort to boost any 3rd party writers or companies.
Not only that, but on the rare occasions when they did use 3rd party content, it was almost always ex-WOTC staffers.
Sorry, I don't really consider including work by Stan! and Monte Cook to be some big nod to the 3PP community.
A nod to the 3PP community would be, say, a feature article on Mike Mearls written back in his early freelancer days, before he had been hired by Monte Cook or WOTC.
Or a blurb about ENWorld.
You know, the sort of stuff Polyhedron was doing.