I'm not much of a Final Fantasy fan, but the quirky Final Fantasy Legend trilogy of Gameboy games left a positive impression on me. The design varies a bit between the three games, but the games offer quite a "smörgåsbord" of playable characters. You might see a party with a slime, robot and mutant elf, perhaps armed with swords, revolvers or magic.
I found out later that the game series is actually called SaGa. The Gameboy games were released back in 89-91 in Japan, but when they made it to NA later they took on the Final Fantasy cloak because of brand recognition. They were never released here in the EU apparently.
The Saga series include a whole bunch of games now, and there are a few remakes of the Gameboy games for the Nintendo DS. The abstract quality of the Gameboy games has a certain charm though, because you can imagine how your characters look with their gear on. In the remakes you're presented with a more static character representation conjured by an artist whose fashion preferences you might not agree with.
That said, here's how I imagined the monsters (Nov.2011).
Of course, in all of the three games, the encounter pictures just represented the general notion of what an enemy looked like (i.e. the Medusa, Scylla, Naga etc used the same picture). With monsters from all three games put into one bestiary, filling out the ranks like that might not be necessary. It's also possible to paint up variations of the original sprites, because they're kinda loose, being so low-res. I already did that with the mouse droids and a couple of other guys.
These are kind of rough, but going through an entire bestiary like this is good for my vocabulary. I also learned a little about posing the figures in a way which engages the viewer (party) and brings a little more life to the figure (though much practice is still needed as some of my poses are kinda wonky). As a concept artist I often end up doing just-standing-there poses.
Sprite reference for the curious.