Citation Bot was one of the first and oldest bots, from 2008. Dozens of similar bots have been written and run on en-WP since. (Notice that it is only used on English and simple English WPs and nowhere else. Virtually all bots are written by English-speakers for one language. Other language WPs don't have this charming little problem.)
I have no doubt that someone has written a new bot that was just started up, and it is now clogging up contribs and Recent Changes. Because most (?) of them are run "client side" on someone's PC, we will never know how many there are, or who runs them.
"Officially registered" bots
are here. Notice how many there are for citations. Thousands more are not registered.
Every year the WMF runs a "Community Wishlist" where any "good editor" can request MediaWiki changes, bot creation/changes, and the like. As you can see in
the 2022 list, every year hundreds of requests are made.
And the vast majority are ignored. Look at the "community vote" for a random item; you can tell which ones are from insiders and "good wikipedians", because those are the ones at the top of the list. Below a certain threshold and you can be reasonably sure the request will be ignored. Note that requests for non-English WPs are routinely ignored.
