JJ = Jej, a town in Afghanistan
JK - jetpack
JL: Jezebel
JM = jeroboam
JN - junction
JO = jumbo
JP - jump
JQ - Jaq
One of the helpful mice in Disney’s Cinderella
JR - jeer
JS - joyousness
JT: juggernaut
JU = jabiru (a large South American stork)
JV - Jaroslav
JW: jackdaw (bird)
JX = Joyeux Noel. And numerous brand names: Javex, Jax, Jumex. Also jeux olympiques.
JY - jury
JZ - Jazz
KA - koala or kola
KB - knob
KC - kinetic