FF & friends in the Marvel Legends line are as follows:
Series 1 Hulk (fought the Thing numerous times)
Series 2 Namon, Human Torch, The Thing, Dr. Doom
Series 5 Mr. Fantastic, Silver Surfer
Series 9 (Galactus Series) Galactus BAF
Series10 (Sentinel Series) Black Panther (made his 1st appearance in FF)
Series11 (Legendary Riders) 1st Appearance Thing
Series14 (Mojo Series) Luke Cage Power Man (substituted for Thing for a while)
Hasbro Series 2 (Blob Series) She Hulk (also substituted for Thing for a while)
There is also the FF line that ToyBiz did that included the Super Skrull (with variant figure) and Dragon Man but they were limited releases and your best chance at them is ebay or a big convention like Chicago or San Diego.
Also, A few decades ago, ToyBiz did a FF line that you can easily find on eBay.
Hope this helps....