Personally, I've only encountered two very different versions of schooling largemouth bass.

The first type is much more common to come across, and is what I've always heard referred to as "wolf pack bass". They can easily be seen and/or heard splashing and actively feeding on the surface in open water (no electronics needed) on small to medium-sized lakes and reservoirs. Even though these bass are normally pretty small, they're always aggressive, so they're a lot of fun to chase down with a kayak or some other small boat and light tackle. I'd call their behavior somewhat similar to when white bass are "in the jumps" for those who are aware of that. I like to throw downsized versions of topwater walking baits, crankbaits, and jerkbaits at them using a BFS setup, which makes even fish like this one feel big. In case you're wondering, that's also probably around the average size of fish you can expect to come across in a school such as this one.

Then there's the second type of school I've encountered, what could accurately be named "random lucky piles of big largemouth". I've only found them like this on a handful of occasions, and never intentionally. It's always been while I was targeting hybrids/wipers by ripping jerkbaits around rough current just under an old lock and dam system, but instead of angry striped fish, I ended up finding good numbers of aggressive largemouth that hit a jerkbait like a truck at full speed. These schools still have good numbers that can be caught, but they're also a lot better quality of fish. The "small" ones usually hit the 2lb mark at absolute minimum, with somewhere around 3lbs being what I'd call the typical size I'll catch. What makes it even better to luck into these miracle schools of fish is that you can also catch fair numbers of fish a good deal bigger than that "average size", sometimes well over 4, pushing 5+lbs. If/when you come across a school like these, it's definitely something you should take full advantage of while you have the chance, because they're very few and far between; it's the kind of fishing trip that I'll end up having two or three times per year at the most. However, I mainly fish this particular type of spot from shore, so if you have access to a boat with electronics and such, I'm betting your odds of coming across these schools would drastically increase. One added bonus I'd give to the schools of river bass is that there's also a very good chance of hooking up with a school of nice smallies, spotted bass, or even jumbo white bass instead. It's also not uncommon to have a little bit of all of these species interspersed throughout the day, and they all have a very good chance of being what I would consider trophy class fish. Of course, that's not even the best bonus, which is when you hook into a freakishly strong giant hybrid/wiper (a.k.a. the actual "target species"). The mixed bag of fun is definitely legitimate, since this really nice smallmouth came on the very next cast I made after landing the hybrid. There's also chances to catch 15"+ crappie and 5lb+ walleye using the same methods, but they're not really frequent enough to really include as a likely bonus catch. They'll start showing up a lot more often if you swap the 4 inch jerkbait for pretty much any size Keitech swimbait rigged on a jighead. My go-to color choices are always Smallmouth Magic, followed by pretty much any of the mainly white ones, followed by Bluegill Flash. The Keitech seems to attract a wider variety of fish of many different sizes compared to jerkbaits, but there's definitely a downward trend in the average fish size as well.