Stupid style trend stuff that applies both to homebrew and to commercial:
Black IPA is out.
Habanero, Ghost Pepper, Jalapeno, and other pepper beers used to be in but are kind of fading out now.
Saisons with stupid additives are still in but starting to fall out of favor.
Overly salted gose is now in.
Sculpins are in (IPA with citrus peel or other fruit flavors).
Anything with loads of brand new hops with stupid names is in.
Meanwhile... Interest in cider is exploding! I am happy about this, even if the USA commercial examples mostly suck.
Other general non-stylistic trendy type things (sorry if some of these might not actually be "trends"):
I agree with the BIAB comment above -- more and more folks are giving it a try and loving it. BIAB is also an especially good option for those wanting to make smaller batches...
Not everyone is making 5-6 gallons by default anymore -- I think most still do, but not all. There are kits now for 1, 2, and 3 gallons for those wanting to start out small or who are only very casually interested in the hobby.
Most homebrewing forums are dead or almost dead, trending more towards generally poor advice from less formal Facebook groups.
Most American homebrewers don't know what LODO is yet, but they will in another year or two. We're still on the far left end of the time scale. My bet is they'll try it out for a few years, decide it's a pain and not decidedly better in flavor, and so it will go by the wayside just like olive oil aeration and so many other fads from 10 years ago.
Dry yeast is being used as much as ever and maybe even more, as more and more strains are being released.
Rehydration is a steady flat trend, as is pitching in accordance with MrMalty.
More folks are trying refractometers and getting super confused about how they work and how to adjust pre and post ferment readings, e.g., complaining of very high FG readings.
Brulosophy.com has become SO huge, it's YUGE! YUGE! They and Denny inspired me to run my own blind triangles this month. My club was impressed and found it as entertaining as it was educational. I think this is going to be happening again and in more and more clubs around the nation, inspired by the likes of Marshall and Denny. Thank you guys.
Many US homebrewers are now playing with water, but meanwhile nobody truly understands it, and in a few cases, homebrewers who become obsessed with perfecting their water may in fact be hurting their beer instead of improving it. My humble opinion.
No one might agree with me on every point, but this is my 2 cents, so accept it for what it is truly worth.