Drawing over the top of eco-printed paper is a lovely project to do with all the samples that accumulate. It can be a meditative process, and can also inspire new ways of drawing.
The photo below shows symmetrical paper eco-prints that I created by sandwiching plant matter between two pieces of paper and wrapping them around a rusty tin, before heating in water. You can see how adding simple line drawings with a black fineliner can create a very striking and organic artwork out of what was quite a subdued print.
Experiment with different types of lines and marks- squiggly lines, dots, light feathery lines, dark bold lines. Keep some areas simple and build others up to create contrast and detail.
If you want help learning how to eco-print so that you can try out these drawings, I have in-depth instructions in my Plant Poetry ebook.