I’m on mobile right now where it doesn’t seem to work quite fully, so forgive me if this is how it already works on desktop - but I think it would be much more valuable if the rhyme search was automatically based on the words I write. Otherwise I will spend a lot of time copying/changing focus/pasting. It could even work like a code autocomplete feature, where it would suggest words or phrases that rhyme with nearby lines, in an overlay next to the cursor.
Another neat addition for crafting lyrics would be to add some way to analyze, visualize and/or constrain the rhythm/stress of the lyrics. It’s one of the main things you need to fit together when writing song lyrics. This could also help give more relevant suggestions for rhymes and synonyms that match a specific part of a rhythm.