I used to buy used & sell them back on Amazon. But now I don't find enough motivation to sell back due to various reasons.

Recently, I have built a bit of collection of books, movies , video games, etc. I share and give away to friends. But I wanted to know what is the best way to donate these things, I can take my collection to Goodwill or Salvation Army. But I feel they resell this stuff way under market value.

Are there any other options?