Here is one that I used for my bridesmaids/bridesman. I wrote it myself. Please feel free to ad other ideas.
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Confidence, shaken.
Fears, they ignite!
Creativity, wakens
and butterflies fly.
He asked me to marry.
I readily said, yes!
I need someone to help me
Through upcoming stress.
You've always been there.
You're more than a friend.
You know who I am.
You know where I've been.
You've stood by my side
Through all of these years.
You've laughed at me and with me.
You've helped calm my fears.
I would be so honored
If you said 'Yay!'
To standing with me
On my wedding day.
Will you be my (insert title here)?
_____