If you are taking a course, ask your professor or TA. Many instructors are willing to share selected solutions for problem sets. Be honest: "I want to check my work and learn from my mistakes."
The ultimate test: explain the solved problem to a classmate without looking at the manual. If you can teach it, you own it. If you are taking a course, ask your professor or TA
The textbook "Quantum Mechanics" by Bransden and Joachain covers a wide range of topics in quantum mechanics, including: If you are taking a course
The keyword "work" in your search is crucial. Students are not just looking for a PDF to copy answers; they are looking for worked out solutions that show the reasoning behind each step. If you are taking a course, ask your professor or TA
(Harmonic oscillators, Hydrogen-like atoms)