remembering my happiest memories (even if it's only 1)
Moving (usually walking outside)
Petting my cat or my golden retriever
Thinking about the people who might miss me if I was gone
Posting here on psych central
Chocolate
Music (I have a play list that starts with my most depressing music and gradually moves me into happier tunes until I get to music that's uplifting)
Mindfulness meditation (we are not our thoughts)
Emotional freedom (tapping)
At the very worst, I tell myself that I need to wait 3 days and if I still feel the same, I can revisit my decision. I actually make a contract with myself
Call someone in real life. I don't even need to tell them what I'm thinking of--just that I was thinking of them and wanted to hear their voice
I think about what I want the people I care for to say about me when I'm gone. If they can't say that about me yet, then I can't go yet

Don't know if any of this will resonate with you but thought I'd offer them up.
Sending thoughts of healing and peace your way