In my study of violin method and technique books, I have found some use in an old edition of the Nicolas Laoureux “A Practical Method for Violin.”
In the Book I, he begins with some exercises quite like those in the Sevcik School of Bowing Technique. These open string exercises would be great for working on reading of open strings, leveling of the arms, and bow distribution. Next he has slurs across strings.
The next section of Book I works on the left hand including intervals and scales. Next, he works on slurring of fingered notes. There are several etudes with duet parts that help develop the left hand.
Other topics approached in the Book I are syncopation, chromatic scales, martele, grand detache, hooked bowings, arpeggios of chords, difficult intonation, and the springing bow. I like some of these exercises for supplements to other study materials.
You would think students should have developed all techniques necessary for playing the violin in Book I, but Laoureux offers three more volumes. I wish this book was available for viola.