K nomenclature (from the IAU and from unofficial sources)

Italics indicate farside features.

Note:
The name KAMP from Apollo 11's Command Module Pilot (CMP) Michael Collins seems to be a crater or craterlet in or near Mare Spumans. It was named KAMP in honour of Michael's family (Kate, Ann, Michael, and Pat). Source: John Moore.

IAU nomenclature
Kaiser
Kamerlingh Onnes
Kane
Kant
Kao
Kapteyn
Karima
Karpinskiy
Karrer
Kasper
Kästner
Katchalsky
Kathleen
Kearons
Keeler
Keeler-Heaviside Basin
Kekulé
Keldysh
Kelvin, Promontorium.
Kelvin, Rupes
Kepínski
Kepler
Khvol'son
Kibal'chich
Kidinnu
Kies
Kiess
Kimura
Kinau
King
Kira
Kirch
Kircher
Kirchhoff
Kirkwood
Kiva (Apollo-16 site)
Klaproth
Klein
Kleymenov
Klute-/
Knox-Shaw
Koch
Kocher-/
Kohlschütter
Kolhörster
Kolya (Luna-17 site)
Komarov-/
Kondratyuk-/
König
Konoplev
Konstantinov
Kopff
Kopff, Rimae
Korolev (Basin)
Kosberg
Kostinskiy
Kostya (Luna-17 site)
Kovalevskaya
Koval'skiy
Kozyrev
Krafft
Krafft, Catena
Kramarov-/
Kramers
Krasnov
Krasovskiy
Kreiken
Krieger
Krieger, Rima
Krishna, Vallis (at Aratus CA, aka "Lorca")
Krogh
Krusenstern
Krylov-/
Kugler
Kuhn
Kuiper
Kulik
Kundt
Kunowsky
Kuo Shou Ching
Kurchatov
Kurchatov, Catena
Unofficial nomenclature
KAMP (at Mare Spumans)
Kant Plateau (see Kant)
Karische Strasse (see Riphaeus, Montes)
Karpinskiy, Rimae (on the floor of Karpinskiy)
Keeler, Rima (on the SW part of the floor of Keeler)
Keill (location unknown)
Kelvin, Dorsa (in Mare Humorum, near Prom. Kelvin)
Kephalinos (Hercules F)
Kepleri (IAU: Protagoras Zeta)
Keyhole (Fauth and Fauth A)
Keyhole (location unknown, on the moon's farside)
Khandrikov (Brouwer P)
Kimbal (Apollo-15 site)
King Y (see link in discussion below)
Kintschotii (IAU: Lansberg)
Kirch pinnacle (the small "island" north of Kirch)
Kircheri (IAU: Malapert)
Kleiber (IAU: Houzeau)
Klepesta (Airy B)
Kohlrausch (location unknown)
Komarov, Rimae (on the floor of Komarov)
Konie c Polski (IAU: Hommel)
Kostinskiy, Rimae (on the floor of Kostinskiy)
Kovalevskiy (Timocharis B)
Kraft (IAU: Marconi)
Kristmannus (Lacus Excellentiae)
Krosigk (Tobias Mayer G)