I literally just make up these cohort names for my own use: they are not "official" in any way. The following groups have appeared in signficant numbers or consistently in the last year or so; I'll remove older/retired groups.
The Rilbrenats are the oldest (and one of the largest) groups of bots on the grid: many of them date from mid-2009. They tend to appear on a region, "pirouette" clockwise, then vanish—at least, if they aren't just a cloud: many have been running so long they've lost all attachments to teleport errors. Most have blank profiles, and they visit both mainland and private estates. My cohort name derives from some of the avatar names—several are named Riley, Brenden, and Natalia—and they carry no inworld scripts. I don't know what these bots are doing, but the distribution and consistency of their operation suggests they're part of a region survey effort. On rare occasions one will get "stuck" at a location for a period of time.
- The BOPs
The BOPs initially appeared in mid-2020 and featured a number of alien-looking avatars (and some are named after viruses). Those seem retired. The large "second wave" of BOPs appeared in early 2021 and uses default avatars and less-provocative names. They visit mainland and estates. The BOPs are run by a hobbyist using simple tools; the operator is interested in AI, analytics, and social graph theory, and the group seems to be a learning project without commercial goals.
- The Hons
The Hons began to zoom around the grid in seriousness in July 2019, although a few appeared in June. My name for the cohort is pronounced "Huhns"—try it with a fake Southern US accent, hon. The bots visit both mainland regions and private estates; their visits are brief but often not as rapid as other cohorts. The pattern of their appearances indicates they're almost certainly gathering land ownership data…although a few seem to have different "missions" at times. Some of the initial Hons had suggestive and/or adult-oriented names; new avatars cycled into the mix tend to prefer nonsense names.
- The Compounds
The Compounds were named because the initial avatars had CompountWordNames, although they've recently shifted to nonsense terms and so are increasingly difficult to separate from the Hons—basically, the only distinguishing feature as of early 2021 is that they seem to move slightly faster on average. They visit mainland and estates and are almost certainly concerned with land ownership data.
- The Zoombies
The Zoombies are a group of quite-old SL accounts that appear to have belonged to real users are some point, but are now being used as bots. Some of the Zoombies are on the grid constantly; others appear to come and go. A "new" gaggle of Zoombies appeared in December 2019 and made it easier to identify the cohort. They visit mainland and estates.
- The Cartographers
The Cartographers are part of an experimental cartography project (you're never guess by the name!) intended, in part, to offer a little competition to GridSurvey. As of August 2020 they're just getting started and will likely be on the grid only sporadically. Very curious to see where this goes.
SurveyTeam is a group of bots began operating on mainland since February 2019 and were later taken offline for retooling; a few still appear from time to time. SurveyTeam reviews land ownership information for regions: parcel sizes, owners, sale prices, prim capacity, ownership, etc., and initially made the information accessible via the web and searchable by avatar or group key (UUID)—that information is public in-world, but Linden Lab does not make it searchable. SurveyTeam was only concerned with mainland.
Guess what! This small group of bots all appear to have rezdays around the middle of 2015. Imaginative naming, I know. Several of them have library textures in their profiles. They visit mainland and private estates. I don't know what they do but they are remarkably consistent.