Without you sharing some context it’s hard to suggest anything precise. I mean, are you talking about sudden frustrations or long-lasting ones? Sudden and unexpected or constant and relentless? Caused by yourself to yourself or by other persons? Caused by some physical issue/pain?
Long walks. This is like magic to me. Plus it helps get in much better shape physically and mentally (better blood flow helps the brain works better or something like that).
Writing, sketching. Longhand with pen and paper. As far as I’m concerned, it’s much slower than typing which also helps thinking slower, which helps take a step back and consider whatever the issue is.
The most useful tool I have: if the source of my frustration is something I can’t change (that’s the keyword: I must know I can’t change it), I will accept it or I will ignore it if you prefer. I will forget about its existence, accept the nuisance, zap it out of my mind. It’s one trick that can be learned with practice (aka with… more frustration), that’s really worth it. Philosophers may refer to that practice as stoicism, but it’s not exclusive to the stoics. For me it’s all about my available energy and time (time I have in a day and time I have to be… alive, on this planet). I have a limited amount of energy I can spend each day, I have only 24h a day and I have a limited amount of days remaining to live. Why would I want to waste them on stuff I can’t change or that will only make things worse (since I can’t change them)? So, I don’t waste my time with those ;)
Without you sharing some context it’s hard to suggest anything precise. I mean, are you talking about sudden frustrations or long-lasting ones? Sudden and unexpected or constant and relentless? Caused by yourself to yourself or by other persons? Caused by some physical issue/pain?