Keel is the characteristic feature of the flower of:
Aloe
Tomato
Tulip
Indigofera
The keel can be seen in the flowers of Papilionaceae plants like beans, peas, and grains. Bean has five different sorts of petals. The largest petal overlaps the 2 lateral petals (simply wings), which overlap the 2 smallest anterior petals i.e, Keel.