Nicotiana Sylvestris! Woodland tobacco - this has a much lower nicotine content then normal tobacco, produces large leaves and is very tall - it is most known for its very unique fragrant smell from the many flowers it produces. Seeds are tiny but easy to germinate and plant is easy to grow.
Nicotiana tobacum "Virginia tobacco" -- this plant can grow up to 7ft tall with huge leaves. It is amazing that more people don't grow this as an ornamental. Also has pink flowers that attract the hummingbird, and the hummingbird moth.
Catnip! Nepeta cataria -- makes cats go crazy, very easy to grow, and obviously fragrant. It is also a great flower to grow to attract butterflies as it produces many many small purple flowers. Generally reseeds itself, and can come back year after year.
Poison Hemlock seeds! Eat it, you die - it is pretty toxic, but for how common it is , it is obviously not a hazard. A lot of bee keepers grow this near their bee housing(?) to help increase honey production as it is a plant that produces lots of nectar for bees and other insects such as butterflies. Likes to grow near water.
Tobacco Plant This plant comes from the same family as the Nightshades and this genus also contains the plants commercially grown to produce tobacco. It contains piperidine alkaloids which are found in poison hemlock, and the pyridine alkaloid Nicotine which has insecticidal properties . Could cause fetal abnormalities in livestock and mso best avoided in tortoises.