Baby shower thank you cards

Hi everyone ,

Some friends from group gym threw a baby shower for me at one of the lady's home .

Most of the people there , I wasn't too close to but we all go to the same gym together . I'm beyond thankful and would like to send everyone thank you cards .

What's the proper etiquette ?

Do you mail it ? Do I ask for addresses ?

Or would I hand them out at the gym ( seems awkward )

Do I do a little extra for the host of the party ?