Image Occlusion Cards
Image Occlusion lets you turn diagrams into active recall cards by hiding specific labels or regions of an image. I used this A LOT for anatomy, where I just quickly pasted in a diagram and created many cards in seconds. My second most commone use case for this was to hide parts of a table, but that's harder to study.
To create one, open Add, switch the note type to Image Occlusion, then paste or drag an image into the editor.
Once the image is loaded, use the rectangle tool to cover the parts you want to test. Each covered region becomes a separate card that hides that information during review.
The tool allows you to resize or reposition boxes at any time before saving, so you can refine cards without recreating them.
Image Occlusion is most effective when you isolate discrete facts per box rather than covering large chunks of information.