Common Nouns:
* Land: country, land
* Lied: song
* Licht: light
* Leben: life
* Luft: air
* Läufer: runner
* Löffel: spoon
* Lehrer: teacher
* Lernen: learning
* Lösung: solution
* Liebe: love
* Lampe: lamp
* Leiter: ladder
* Linie: line
* Lücke: gap
* Liste: list
* Lage: location
* Laden: shop
* Laut: sound
* Loch: hole
* Leib: body (often used in compounds like "Leibspeise" - favourite food)
* Leiter: ladder
Less Common Nouns:
* Labyrinth: labyrinth
* Labyrinthitis: labyrinthitis
* Luchs: lynx
* Luder: lewd woman, prostitute (offensive)
* Lunge: lung
* Laster: vice, flaw
* Lichtspielhaus: cinema
* Lyrik: poetry
* Lohn: wage
* Lappen: rag
* Lappen: rag
This is not an exhaustive list, but it gives you a good starting point. There are many other German nouns beginning with "l," and the specific nouns you might encounter will depend on the context.