I like
Tamara. It sounds distinguished and old-fashioned in an enterprising, non-aloof way like someone who is into herbs and urban gardening. I like
Mara as a nickname for
Tamara but prefer it in full.
I dislike
Tammy. The is something spammy about
Tammy like someone who sends emails about their latest multilevel marketing pursuit.
Tamsin is one of my favorite names right now, but it doesn't have any nicknames that I could live with hearing on a regular basis.