The one that worked for me like charm, so I share it whenever possible is:
do something you've never done before every single day and acknowledge it by making a note of it in a journal at the end of the day with a quick comment on it. Can be tiny - trying a new flavour of coffee, scent of bubble bath, walking down a new street in your neighbourhood. You can start with lots of easy ones - listen to new radio stations, new podcasts, new music on spotify and you tube, download new apps, try a new game, a new author, subscribe to be sent a poem a day. Try exercise as part of this experience - try a new type of dance class - just once - or weight lifting or wild swimming. No need to do anything twice unless you want to.
Gradually add some slightly more daring things - visit a new place, do a zipwire or other physical challenge (juggling, tightrope, high swing, climbing a tree, abseiling, canoeing, horseriding etc). Learn a new language, start a course in a new subject - pottery, pattern cutting, etc. Be socially braver: speak to a stranger at a party (obviously once lockdown is over), speak first at a meeting, give a public talk etc. Overcome invisible life blocks (eg if you've never made a will/set up a savings account/don't know how to do online banking/create a website etc, do it.
You can google lists online of silly and brilliant and brave and sensible new things to do. I can link you to some if you want to PM me.
I did this and it got me off antidepressants after a decade of being on them. I have been off them for two years now. I still get bad days but if there are too many in a row, I go back and do it again.