The mind hack I use most often is "It is what it is"

I do this as well, but I call it "acceptance".

Another mantra that improves my life when I encounter strife or social anxiety is "it's not really about me".

I don't know if this counts as a hack but the most recent one revolved around a trash company that overloaded itself and could not pick up trash for a week. I temporarily stopped using large trash-bags and instead put trash daily into disposable shopping bags. It turns out I can fit about 60% more waste in their garbage container using disposable shopping bags than I can using the 30-39 gallon bags. This might be useful for people that rent two or more of the garbage containers. To list all my hacks would need a blog.

Well. Where is your blog?

I used to have one listed in my profile but I removed it for lack of interest and nuked the VM it was running on. I maintain it locally and may put it back online some day.

Practicing (ie. trying to the improve skill of) fasting. I have the best results when I start after lunch and drink bone-broth on the fasting days; I treat it like a improvable skill, not as an exercise in sheer willpower; fwiw my record is 15-days.

Doesn’t bone-broth break your fast?

You're question is kinda rules-lawyery. It would break a water fast. Joe Cross fasted for 60 days on vegetable juice and made a movie about it; he lost 100 pounds, but yes its not a water fast, but that's somewhat the point of my comment, that there's more to fasting than simply not eating.

Fasting and OMAD. Eating only once a day fixed many issues I had (physically) but also helped me continuing eating the way I like: until I'm almost exploding. It turns out doing it only once a day is quite healthy.