In principle you can grow almost all woody or lignifying plants as bonsai, as long as they tolerate cutting and pruning well, whether they are trees, shrubs or semi-bushes. Some species may grow too quickly and luxuriantly or may form too much or too expansive foliage to adhere to formal stylistic guidelines, but are still viable as miniature ornamental plants.
Regardless of the choice of the plant, this form of cultivation takes a lot of time and care, and there are different philosophies: While it is very common to dig up large plants and cautiously cut them back to a smaller size and then let them recover, the cultivation from seeds is not too frequent, since it delays the actual bonsai growth phase by about 3 years. Still, when starting from scratch it is possible to choose among various seedlings, and as such this method offers the greatest freedom of design.
In addition you have the possibility to raise species which are very rarely available as ready-made pre-bonsai, or use exotic plants as indoor bonsai and thus combine two very special horticultural passions.