Here is a short list of actions that many subs are already engaging in: private days (example - Solidarity Tuesdays, or on the weekends); restricting the topic of the forum (example: restricting to just pictures or gifs of one personality ); narrowing the topic of your forum (see the example of r/Wellthatsucks; widening the topic of your forum (see the example of r/interestingasfuck); redefining the topic of the forum (see r/nofans, previously a NSFW sub, switching to "lovely passive PC coolers"); r/iphone is posting only pics of Tim Cook “looking dashing”.; r/tall forced to reopen under threat of being removed as mods, users are posting John Longiver pics; r/horny is now a "christian minecraft server";
https://cybre.club/files/webpublic-9ee42956-6449-4bf9-b1f6-935b24e73201