What can you use for bsamin at havdalah?
For example, are any of the following ok – cinnamon, rosemary, tea bags, ground black pepper, plants from outside?
You can make a besamim on any plant that has a pleasant smell (M:B 297-9). It is permitted to make the bracha on cinnamon etc. even though it is a food, and even if it is in your home in order to eat. It is however preferred to use besamin that is designated for using for havdalah. The reason is, even though it is in the house in order to eat, when it is picked up for havdalah it is meant for smelling purposes. If the cinnamon etc. is used specially for havdalah, then it would also be considered the preferred way.
Taz 297-7 Tosefes Shabbos 297-9, M:B 297-10, Shmiras Shabbos Khilchoso 61-11, ftnt. 30, Kovetz Halachos Shabbos pg.750. The Chazon Ish O:CH 35-(1-6) held not to use foods that are meant to eat. PIskei Teshuvos 297-4.