I just uploaded a PDF copy of Compute!'s Guide to TI-99/4A Sound and Graphics with the book's programs on two DSK files to use on Classic 99.
I was obsessed trying to find the complete digital versions of the programs but was only able to find two or three out there, so I decided to copy the programs directly from the book and debug the OCR errors myself. The OCR was acceptable in most cases; most errors were lowercase l/i/1 confusion, lowercase o/0 errors, interpreting W as V7, changing the $ to S among others. Good practice and I had some fun playing the games.
I tested the programs to the best of my abilities, hopefully they are bug free, but I do not guarantee it; that's my disclaimer.
Here's the link: Compute!'s Guide to TI-99/4A Sound and Graphics