general

• https://www.sumatrapdfreader.org/free-pdf-reader.html
• zettelkasten
• https://www.docformats.com/
• https://alternativeto.net/

transcripts & text

• https://www.youvideototext.com/

studying

• ap: https://fiveable.me/
• https://hemingwayapp.com/
• textbook solutions: https://quizlet.com/explanations requires quizlet premium