Drawing from sculpture is a great way to improve! The Baroque painter Peter Paul Rubens used to say that drawing statues is the key to understanding form and light well. If you live in a city with lots of classical statues, go check them out with your sketchbook.
There is also this excellent collection on Sketchfab
https://sketchfab.com/alexdubnoff/collections/classic-sculpture-af4c3bf799734d3197005bf3beda0ad4
You can download some of the Sketchfab sculptures and use 3d software of your choice to adjust the lighting, texture, and many other factors.
There are also places that can sell you plaster casts of famous sculptures, for example
https://www.capronicollection.com/
but this can be rather expensive.
I recommend Sketchfab and a free 3d suite like Blender for beginners.
Here is a beginner tutorial set for Blender users:
https://www.youtube.com/watch?v=uOmYInaX-wE
There is also this excellent collection on Sketchfab
https://sketchfab.com/alexdubnoff/collections/classic-sculpture-af4c3bf799734d3197005bf3beda0ad4
You can download some of the Sketchfab sculptures and use 3d software of your choice to adjust the lighting, texture, and many other factors.
There are also places that can sell you plaster casts of famous sculptures, for example
https://www.capronicollection.com/
but this can be rather expensive.
I recommend Sketchfab and a free 3d suite like Blender for beginners.
Here is a beginner tutorial set for Blender users:
https://www.youtube.com/watch?v=uOmYInaX-wE