You can use sticky foam pads for a 3D effect or simply glue the toppers to the card base.
Boots and Flowers Square Card Toppers for Card Making, Journals, Tags, Scrapbook
6 Cats With Flowers Square Card Toppers for Card Making, Journals, Tags, etc
Afternoon Tea & Flowers Square Card Toppers for Card Making, Journals, Tags, etc
Birds and Birdhouses Square Card Toppers for Card Making, Journals, Tags, etc
Paper Flowers Flat Square Card Toppers for Card Making, Journals, Tags, Floral