Here are a few things to get you un-stuck. These are by no means the be-all and end-all of what's out there, they're just the first things that came to mind as potentially being useful.
Brentalfloss - He's a guy with a background in music theatre and composition and he puts lyrics to video game songs (check out the rest of his channel, if interested). This is the first part of a series of really interesting videos he did called 'Lyrics 101', which he did to help you write lyrics. So watch them, they're really good and helpful despite how inapplicable they may be to your chosen artform.
An Online Rhyming Dictionary - this should be self explanatory.
A WikiHow page dedicated to overcoming writer's block - As with all WikiHow pages, what it says is obvious and cliched, but it could still apply to you. If nothing else at least it may get you thinking.
http://thesaurus.com/ - Again, hopefully self explanatory.
-E
