Let me add some ideas for oxytocin: Have a purring cat around you. Have skin contact with people you love. Go for conscious slow sex.

Serotonin: All kind of workouts. Sweat in a sauna. Have a hot bath. Cold exposure works also. Expose yourself to beautiful art you like. Listen to your favorite music.

Dopamine: Set yourself goals and go for them. Notice what you have achived already. Sense that you are on a good trajectory. Reward yourself with something you enjoy.

Endorphine: Smile. Gift something to someone you like, maybe just your time and attention. Expose yourself to pleasant situations.