Hello ,
Library Genesis
This is the go-to site for most ebooks. Some of the engineering textbooks comes with the solution manual as well. Searching for the title + “solution manual” will give you some results.
Zlibrary
This is another site where you can try if you can’t find it in Library Genesis.
You may need an account if you exceed the download limit. If you do not like to use your personal email, you can opt to use a temporary mail.
Ch36650lut10n5
A website which has textbook solutions ripped from chegg. It has quite a lot of books and free, no need to sign up or give any credentials. You can find many textbook solutions that are not on libgen or zlibrary.
Slader
If you are looking for textbook solutions for free, check Slader. You have to sign up to access materials, after that you can access many solution manuals written by teachers and professors.
They recently installed a limit, trying to make access to answers a paid service unfortunately.
Studylib
As the name itself says it’s like a library, where you can have a large number of assignments and solutions. You can also share your notes with your friends which would help them to solve the problems. It will provide you with a solution for all the subjects. You can also upload your documents and find the solution.
Pdfdrive
An online PDF search engine that lets you search, preview and download PDFs. According to the site as of right now, there are over 75 million eBooks, magazines, articles, and more that are indexed and discoverable directly on PDF Drive.
Sci-Hub
Great place for finding published journal/conference papers that are (usually) paywalled.
AudioBookBay
If what you want is audiobooks then audiobookbay is the go-to place.
Feedback and appreciate the share please, it will motivate members around!