At 40km south from Agadir, there is the Souss-Massa river national park
At about 80km east from Agadir, there is the city of Taroudannt, which is worth the visit if you don't plan to visit Marrakech or other big historical cities.
The coast northern to Agadir has very nice and accessible beaches, like Taghazout at 15 km. You can get to these towns using the Zetrap bus line: 60 and 'RATAG' bus line: 12 that leave from the center of Agadir. Bus Number 32 runs every 20 minutes or so north on Boulevard Mohammend V 12 Dh.
Imouzzer with its famous cascades is located about 60km northeast of Agadir, although the trip through the mountains will take longer than the distance suggests.