Illustrious rhymes with:
industrious, industrious, demetrius, dimitrius, dimitrius', industrious, vitreous, aquarius, curious, deleterious, delirious, demetrius, denarius, dimitrius, dimitrius', furious, glorious, gregarious, hilarious, imperious, industrious, inglorious, injurious, laborious, lugubrious, marius, meritorious, murias, mysterious, nefarious, notorious, pancreas, penurious, precarious, serious, spurious, stradivarius, tavoulareas, various, vicarious, victorious, vitreous