Two that stand out for me.
Karen Carpenters Ticket to ride is streets ahead of the Beatles version.
And the Pinky and Perky version of Rainbow Valley is better than Lovin Spoonful's version.
The Beatles are just so superior to Karen Carpenter who always sounded to miserable on her songs.
As someone else has pointed out Rainbow Valley was by The Love Affair. The Lovin' Spoonful didn't record songs like that and I can't somehow imagine Pinky and Perky doing one of their songs.