You can use sticky foam pads for a 3D effect or simply glue the toppers to the card base.
Colourful Birds in Flight Square Card Toppers for Card Making, Journals, Tags
6 Stained Glass Hummingbird Square Card Toppers for Card Making, Journals, Tags,
6 Cats With Flowers Square Card Toppers for Card Making, Journals, Tags, etc
6 Flower Barrows Square Card Toppers for Card Making, Journals, Tags, Floral