A star of David is a traditional design for a Bat Mitvah; replace solid lines with rows of hearts in the girl's favorite color for a twist. Another idea is pinning a miniature fabric prayer shawl to the card or fashioning a torah from paper and affixing it to the card as decoration and as a place to insert money. Otherwise, give a tree of life a unique look by incorporating objects from the girl's life into the branches.
Ready-made prayer shawl and torah cards are available online from Papyrus. A shofar blowing confetti, star-shaped or otherwise, is another novel idea incorporating a traditional symbol. Give the card a personal touch by cutting a photo of the girl into a star of David shape and affixing it to the front.
The tree of life is a classic theme for important celebrations. Draw the tree from scratch or use a design template or ready-made card and paste the objects onto it. These objects may replace leaves or be placed on leaves. Ideas include musical instruments or music notes, books, ballet shoes, a pony, ice skates, a dog or cat resembling a beloved pet, or flowers. Such card decorations are available from craft stores.