In the episode "Beddy Buy", Garfield and Jon sing a song about what they'll buy in the store ("Hello Charge Card! Money in the Bank Bye Bye!").
The song Garfield sings in "First Class Kitten" when Nermal asks him where he's sending him. A bouncy tune about how Garfield wants Nermal far away because he's too cute.
In "Green Thumbs Down", we have a beautiful song about Jon's new vegetable garden.
The entire episode "Truckin' Odie", wherein Garfield (somewhat snidely) narrates an adventure of Odie's. Starts with a lone banjo on a stage and builds into a rousing trucker-country power ballad.
"Garfield Rap", an "I Am" Song rapped by Garfield himself in the episode of the same name. As a bonus, count all the rock and rap Shout outs in the video.
Many of Orson's songs. "Banana Nose" from the episode of the same title. The song from "Shell Shocked Sheldon" to convince Sheldon to hatch. Two Heartwarming ones in "National Tapioca Pudding Day" and "Mud Sweet Mud". The 50's theme song from "Goody-Go-Round", and one from "No Laughing Matter". Also, "Superstition", and "Wade, You're Afraid" from the episode of the same name.
Lanolin only had three songs, one in "Unidentified Flying Orson", where she was singing to Orson not to believe everything he reads, a heartwarming one in "I Like Having You Around!" to her brother of said title, and in "Sleepytime Pig", an upbeat workout song to help Orson get to sleep.
Sadly, Bo only had two songs, one in "The Bad Sport" where he talks his sister into trying new things like playing a new game and the one in "Keeping Cool" when he was singing to Orson about keeping his cool. His voice and singing sounded much cooler in the Spanish version.
Roy's song from "The Impractical Joker" was actually pretty catchy. In comparison, his singing voice sounds better in the Spanish version. His jazz-blues song from "Cock-a-Doodle Dandy", sounds good as he keeps on singing. His song from "The Legal Eagle" is catchy too and his voice sounds better and deeper in the Spanish version.
Wade's not normally a good singer, but he sounded so awesome in "Flop Goes the Weasel" when he changed his voice and sounded more confident. "Oh, yes, I am a hero! I mean if that's OK!" He also sounded pretty good in "Orson Goes On Vacation". "What Harm Can It Do" could also be this; the electric guitar-led accompaniment is particularly awesome.