I practice breathing exercises and (try to) meditate. I usually do an "inhale for count of four, pause for two, exhale for four, pause for two, repeat" and just keep myself focused on counting the length of my breath and pauses. If my mind starts wandering or spiraling, I refocus on the sensation of breathing and counting. It's very helpful for oncoming panic attacks and other short bursts of anxiety. I've also found that trying to keep to a short daily meditation practice (as in, 2-5 minutes, usually when I wake up) helps, but it's the sort of thing that doesn't help until I've got at least a month of it under my belt. YMMV If I'm having anxiety about a specific thing, I might sit down, either with my therapist or with a friend, and list all the worst case scenarios of whatever I'm worried about, and then we talk about "are these fears realistic" and, if they are, about what I could do if they happened. Having a plan helps. I don't do this one alone though because without somebody else to talk it out, I just make myself sick with anxiety and can't actually evaluate my fears on my own.
Going out on a run has been helpful for me because i can't really think about anything else when I'm doing it, but it only ever works as a short-term fix.
I like watching streamers or gameplay vids. Obviously this isn’t a good idea if the stress is caused by a problem that you need to take action to solve, but I find it relaxing as a distraction from anxiety.
I have clinical anxiety so stress is a huge and multifaceted thing for me. I deal with various manifestations in different ways. For intrusive anxious thoughts, nothing but medication really made much of a dent. Keeping on top of self care to the best of my ability helps get me through the rough patches a little easier. Aside from basics like food and drink, I’ve found that it’s vital to include things that make me feel good. Good physical sensations like a warm shower or a nice ASMR video. Good experiences like a show I enjoy or a conversation with a friend. Good about myself like getting a healthy amount of exercise or dressing up a bit. If I’m stressed about doing work, I try to use whatever I can to make it easier to slip into it. I focus on setting up my workspace all nicely first because it’s easier for me to decide to do that than decide to do the actual task, and once my workspace is all ready to go it will be easier to decide to do the work. I put on music that will help me get going. I ask a friend if they also have something they need to get done so that we can get together and keep each other company and on task. Videoconferencing works fine if we can’t physically be in the same space. I talk through my fears with a therapist or friend, or think through them myself depending on what’s available and what’s needed. I try to be kind to myself when I realize I’ve exceeded my ability to cope.
Making lists sometimes helps me. Like I'll make a list of all the things I have to do for the foreseeable future then break each thing into more steps. Eventually there will be a couple of things that I can do right at that moment that are pretty small and doable and the satisfaction of crossing stuff off makes me a little bit less stressed feeling. Reorganising or tidying something often helps to. It's a ""productive"" task that requires a lot of focus and has a measurable outcome.
I go for a walk, draw, or read. I'm trying to cut down on reading because it eats up hours and hours and I end up more stressed because I've procrastinated. So keep an eye out for coping mechanisms that lead to more stress I guess. Sometimes I do something physical and mindless, like washing dishes or cleaning with music blasting in the background. That helps, because it makes my mind shut up for a little while and I've been productive by the end of it. Coloring helps too, actually, because I don't have to come up with the idea myself and I can do it even when I have artist's block. Sorting things, I'll second that; I started cataloging my books a while ago and I come back to it when I feel like my mind is tying itself in knots. It's basically data entry; find the info, put it together, type it up; no analysis necessary. That's all stuff that works for me, so who knows if it'll do you any good, but I hope at least some is helpful.
