It is a LOT easier to build things from flat geometric shapes (or frilled one, if you like granny square flowers or whatnot) than it is to make a fully shaped piece with complex sculpture.

Quilt patterns:
https://www.thesprucecrafts.com/quilts-designed-with-squares-and-rectangles-4051124
https://www.generations-quilt-patterns.com/free-quilt-block-patterns.html
https://quiltingcubby.com/quilt-ideas-for-10-inch-squares-that-make-beautiful-quilts/
https://newquilters.com/9-nine-patch-quilt-block-patterns-precut-squares/
https://blog.shopmartingale.com/quilting-sewing/give-me-quilts-with-squares-and-rectangles/
https://www.favequilts.com/Patterns-for-Quilting/Simply-Stunning-Strip-Quilt-Patterns
https://www.createwithclaudia.com/2019/04/half-square-triangle-tutorial/
https://www.coralandco.com/blog/2019/09/13-free-triangle-quilt-patterns-for-beginners.html
https://www.favequilts.com/Patterns-for-Quilting/Terrific-Triangle-Quilt-Tutorials-Triangle-Quilt-Patterns
http://finitegeometry.org/sc/16/quiltgeometry.html
https://blog.accuquilt.com/inspiration/patterns/quilting-patterns-using-circles
https://www.internationalquiltmuseum.org/sites/default/files/pdf/geometric_patterns_at_iqm_lesson_plan.pdf
https://www.generations-quilt-patterns.com/quilt-block-patterns.html
https://www.fatquartershop.com/free-quilt-patterns

One approach would be to print out or buy some quilt templates and then use those to make shapes. Circles you just go in a spiral, squares or triangles you go back and forth, until it's the right size.
https://www.ebay.com/b/Quilt-Templates-Stencils/116680/bn_7562967

Modular origami:
https://gurmeet.net/origami/
https://www.polypompholyx.com/2017/01/modularorigami/

Stained glass patterns:
https://pdqpatterns.com/index.php?main_page=index&cPath=27