If you want to jump in, go right ahead! The gist is, pick 10 monsters and build a mini setting around them. How do they interact? Who was there first? Who wants what from who?
If you do one, tag it #tenmonstersetting
https://mythopoeicrambling.wordpress.com/2019/04/18/shane-wards-ten-monster-setting/
https://theamateurdungeoneers.blogspot.com/2019/04/ten-monsters-setting.html
http://thebrookmerechronicles.blogspot.com/2019/04/10-monster-setting-fiend-folio.html
https://www.theseoldgames.com/2019/04/the-3-toadstools-and-tenmonstersetting.html
Here's a few more!
https://belchion.rsp-blogs.de/2019/04/24/tenmonstersetting-spinnen-im-regenwald/
https://gundobadgames.blogspot.com/2019/04/ancient-war-for-rainy-isles-my-10.html
And a new one: https://savemycampaign.wordpress.com/2019/05/13/10-monster-setting/
http://slantingpassages.com/blog/2019/4/27/ten-monsters
https://ravenousambience.blogspot.com/2019/05/10-monster-setting-dreadshores.html
https://euphemnion.tumblr.com/post/184919132346/ten-monster-setting
https://belchion.rsp-blogs.de/2019/05/22/tenmonstersetting-valley-of-sorrows/
https://weirdwonderfulworlds.blogspot.com/2019/05/four-10-monster-settings.html
https://archons-court.blogspot.com/2019/05/the-flesh-descends-10-monster-setting.html
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https://nerdhogg.blogspot.com/2019/05/10-monster-setting-absolems-pearl.html
https://industriesofinferno.wordpress.com/2019/06/11/10-monster-setting/
http://throneofsalt.blogspot.com/2019/05/10-monster-setting.html
If you need a bit more help Chris Hall came up with this:
After I suggested this Chris Hall came up with this handy list:
Pick a semi-intelligent humanoid (could be goblins, apemen, subhumans, etc.). Pick an undead. Pick an ancient fey race. Pick a giant/ogre/troll race. Pick a type of great wyrm or lizard. Pick something aerial. Pick something to lurk in the water. Pick something from another dimension (demon, gith, illithid). Pick a classic creature from mythology (medusa, satyr, minotaur, etc.). Pick some foul crawly thing that infests the underworld. Something like that. Then I’d give each a twist.