Help — crafty folks, send me some ideas

My daughter sewed nine adorable pairs of christmas lounge pants for the cousins, and I (knowing our limits) ordered LL Bean red long sleeved tshirts for the tops. They have arrived, and my husband thinks that they are too plain, and he is probably right. I have done the Soule Mama fabric paint silk screen trick before, that is easy and do-able for us, but I need a great picture or symbol to put on them.

I can’t make individual names, I will go crazy, but I could do a big initial letter for each family, or a symbol.

Any suggestions?