This is a good place to start for puzzles https://lichess.org/training/themes If you set the difficulty level to -600 (Easiest) or -300 (Easier), I find that I can do a lot of puzzles and find the solutions quickly. This builds up the patterns in my mind by repetition of the theme. For me doing 100 easy puzzles versus 10 hard ones in an hour is a better learning opportunity.