I've been sightreading Bach's chorales for quite a long time now in order to improve my sightreading. I've found them quite useful to improve my "vertical" reading.
I love Bach and I would love to be able to sightread the Two- and Three-Part Inventions and the WTC. The problem is that these have quite a different type of "writing" compared to the chorales.
My question is: what pieces of music (not necessarily Bach's) exist that are easier to sightread than those and would enable me to learn the fundamentals needed to play the Inventions and the WTC. I'm looking for something like the Chorales, that is, lots of pieces which are similar between them.