You can use sticky foam pads for a 3D effect or simply glue the toppers to the card base.
6 Cats With Flowers Square Card Toppers for Card Making, Journals, Tags, etc
Boots and Flowers Square Card Toppers for Card Making, Journals, Tags, Scrapbook
Afternoon Tea & Flowers Square Card Toppers for Card Making, Journals, Tags, etc
For Mum Mother's Day Square Card Toppers for Card Making, Journals. Birthday