I've seen two bot patterns (called out by the users themselves in context) in years of using reddit; both rely on the bot accounts having karma-farmed the system (and these include adding to their karma farm):
-
(a) Repost-bots: they take a good image content post from some time ago which may not have been popular at the time, or posted in a more niche subreddit, and repost it as their own content in a popular subreddit a period of time later, using very specific timing to hit their target audience. Commenters call this out but a lot of folks just click on images and upvote and don't read comments (memes, etc.), so the accounts tend to have longer lifespans.
-
(b) Comment-bots: they are similar to the above, but instead farm good content comments which have low or few upvotes (typically because the comment was posted "too late" in a thread, timing is everything when posting on a massively read thread - first in gets the upvotes so to speak). These get called out as well by other commenters more successfully and people start to block those accounts, so I see the comment farm bot accounts rotate frequently and have short lifespans. You see this in a lot of News articles.
Sorry no examples on hand, but spend enough time and you see the patterns (or, shall I say used to) - I've left Reddit to only one niche hobby now so my experience is out of date by a year or so (i.e. not aware of the "AI bot" revolution patterns). $0.02 hth
Edit: I should note that not all bot accounts are bad, my niche hobby has a subreddit specific bot (think like an IRC channel bot) which farms the upstream vendor content (website, twitter, youtube, etc.) and posts in the subreddit for everyone's benefit. This type of bot is clearly labeled as a bot and approved by the admins of the subreddit, just like iRC.
We have two Fediverse patterns emerging (talking both mastoverse and lemmyverse here) which have caught my eye:
Names withheld to protect myself from getting griefed.