Dictionaries
Dictionary.com
MacMilliandictionary.com
Merriam-webster.com

Thesauruses
Thesaurus.com
MacMilliandictionary.com
Oxforddictionaries.com
Collinsdictionary.com
Merriam-webster.com

Rhythming Dictionary
Rhymedb.com
rhymer.com
rhymezone.com

Sayings/Idioms/Phrases
TheIdioms.com
List of proverbial phrases (wikipedia)
List of phrases and sayings

Songwriting Prompts
reddit.com/r/SongwritingPrompts
writersdigest.com
fawm.org
lyricideas.com
thestorystarter.com
learnhowtowritesongs.com
watchout4snakes.com
redd.com/r/WritingPrompts

Song Name Generators:
Songname.net
modplug.com Songtitle Generator

Bandname Generators:
leonatkinson.com
tunevault.com
bandnamemaker.com
blamepro.com
elsewhere.org

Writing Pompts
Fabula Storytelling Cards
The Story Engine Deck

Songwriting Software
Masterwriter.com
lyricstudio.com
Songcraft.io
theselyricsdonotexist.com
boredhumans.com
Screenplay.com
Misc
Perodic Table of Storytelling
speedsongwriting.com
allaboutsongwriting.com
nicholastozier.com
masterwriter.com
writersdigest.com
ted.com/topics/storytelling