In case you missed it, there's a list of unusual-but-popular hashtags to follow on the Fediverse at:
鉃★笍 https://fedi.tips/fun-and-useful-hashtags-to-follow-on-mastodon-and-the-wider-fediverse
Let me know if I've missed any tags! 馃檪
To use this list, copy-paste a hashtag into the search box in Mastodon etc, select the tag to see its results and then click "follow" to follow it. If you want help with how to follow hashtags see the guide at https://fedi.tips/how-do-i-follow-hashtags-on-mastodon-and-the-fediverse
@FediTips An occasional one is the #WorldBollardAssociation, for vehicles coming off second-best in fights with traffic-management bollards.
(May not match your inclusion criteria, but it's one I like).