There are big, overarching top-down trends, and there are little-bitty baby trends that have a way of growing into bigger ones. A big trend right now, for example, centers on certain firms that passed out enormous checks to startup founders in recent years and drove valuations sky high in the process. It turns out this strategy doesn't work as well as they'd anticipated, and some of these same firms are now splitting up with some of their partners and asking their own investors for a lot less capital.

Another big trend? Venture firms that are more aggressively investing in publicly traded companies given that many have seen their share prices hammered in the downturn. (We began seeing this trend back in January and the WSJ notes that it is only picking up steam.)

Now here's a new baby trend that's interesting: new firms that are so niche that, at first glance, it's easy to laugh off their focus.

A venture firm focused solely dedicated to oral care and not something, um, a little broader? A firm that's focused on tech that can help detect and contain wildfires? (No way.) How about a venture firm that's dedicated to backing and building psychedelic businesses alone?

As it happens, these outfits exist, and two of three of them have this week announced moderate-size debut funds, while the third suggests it's on a path to doing the same; viewed together, they create a picture of how the industry could potentially look over time.

Let's take the first firm, the one focused on oral health alone. Called Revere Partners, the New York-based outfit -- which counts among its partners Mark Zuckerberg's dentist father, by the way -- seems still to be raising a fund. (It announced in a late-September press release that it is "launching" its fund, which is code for: we don't have a fund yet exactly.)

You might imagine in this case that a lot of wealthy dentists are pooling their money together to invest in technologies that they know could upend their industry. That could well be what's happening. But give credit where it's due. Dental care is a huge market that's growing as the world's median age rises. It's expected to surpass $230 billion by the end of next year, according to the Office of the Actuary at the US Centers for Medicare and Medicaid Services.