As an example, Spanish.SE started a satirical translation golf mocking the official announcement on why Monica Cellio was fired. Did other SE websites have interesting reactions to the recent controversy?
NB: This post is created to capture all the reactions in one place, rather than to discuss the controversy.
The controversy went virtually unnoticed on Language Learning Stack Exchange: it was not discussed in the chat, nor in meta posts. No mods resigned or went on strike; nobody threatened to delete their account. Two of the three mods signed the open letter.
As a mod on that site, I am not aware of incidents on LLSE related to the choice of pronouns or disrespectful behaviour towards LGBTQ+ people.
Update 24.10.2019: This controversy is far from over. One of the mods on Language Learning SE announced that he will be going inactive.
Update 14.01.2020: The mod who previously announced a period of inactivity has resigned from moderating.
That depends highly on what you define as "reaction". On Information Security, the general reaction to the topic was that people showed their disappointment in how Stack Exchange is handling the entire situation.
Two moderators resigned, and another moderator expressed continued erosion of trust to the company. I personally stopped any moderation tasks, such as voting, editing, flagging and reviewing. Given the amount of low-quality questions that subsequently came to the frontpage, I assume several others did the same.
Was there any snarky or light-hearted reaction to brighten the moods? No, not that I am aware of. People felt hurt, people felt disrespected, people felt like all the work and effort they put into the community was essentially wasted. And that was not a good feeling.
After a brief discussion with a moderator, I continued my moderation tasks again. Not because I suddenly enjoyed providing value to a company that doesn't value me, but because I care about the community and want to see it in good shape - though this is more of a personal anecdote than anything generally related to Sec.SE.
In Spanish.SE there is a contest to see who can translate the first response by Sara into Spanish with the least characters. If you understand Spanish you'll some translations are quite on the satirical side.
In Worldbuilding.SE where Monica had been a moderator, there was some grief. One moderator resigned, and a user made an ode to her.
It went essentially unnoticed on Server Fault (SF).
I've watched most of the posts and discussions here and in the moderator's chat room, but I haven't participated too much. One of the other SF moderators has had about the same (minimal) involvement, and the others haven't been involved at all.
There isn't really a community on SF; there's essentially no chatting and no discussion in comments, so the pronoun issue doesn't ever come up (not that I've ever noticed, anyway).
Seems like it doesn't even reached into Movies and TV. so it's not affected and it's running as usual. This doesn't mean nobody there hasn't heard of the any news, but the current situation and drama had no effect on it's daily activities.
On Interpersonal Skills, we decided that the best way to support our mods was to do all the mod work for them.
We also had a discussion to know if there was anything we could do to help appease things on SE. The conclusion was mostly "no, we can't, it's not in our power".
Almost nothing moved on Electrical Engineering. No meta posts, no mods resigning or stopping activity. As far as I know, they didn't discuss the matter publicly (in a post or in chat) and none of them signed the open letter.
The only reactions I know of were this comment on chat, actually made by me:
No moderator stepping down in support to Monica Cellio, here? EE.SE is like a rock. Everything is falling apart around, but down here, things always stay the same. It's kind of reassuring, actually.
... which didn't trigger any response whatsoever (well, I didn't take offence, because my message was probably completely unnecessary).
And a user who retracted his close vote on a bad question, because he was on strike (the question got closed anyway and will likely be deleted soon). The user didn't seem to do it on another post.
Apart from that, business as usual.
It didn't reach Super User either as it's more of a technical site and no resignations or changes so far. Everything keeps running as before.
"There was a bit of discussion on chat but the core community are good folks so no major impact there." -- Journeyman Geek
pronounas a keyword and it returned zero results.