I am no poet or lyricist, but a humble drudge whose beat is nonfiction prose. But I have a reader of these posts, Jeremy Desmon, a New York musical theater lyricist, who wonders whether I would have any interest in his online rhyming dictionary.
So I took a look at RhymeHamster. It offers lists of perfect rhymes and slant rhymes. I tried "gray," and the screen erupted with possibilities in varying syllables. I tried "orange" and was told, predictably, that there is no true rhyme in English.
It's not an OED of rhymes, limited to 122,000 words, but it has 10,000 or so modern words, including phrases, names, places, and brands. It offers categories: "Internal Rhymes hiding inside longer words. Wildcard Rhymes for when you’re one sound away from the right word. Stretch Rhymes for deliberate near misses that still sing. Homograph Pairs for words like wind and tear: one spelling, two sounds, a button for each."
It won't likely give you an inspired combination to match Richard Wilbur's song from Candide about Pangloss's veneral disease--"Without the little spirochete / We'd have no chocolate to eat"--but I think it might serve most of your purposes.