Hi, Kimber An:
Yes, certainly check out
Manybooks and
Feedbooks, two major players.
Many people here prefer Feedbooks over Manybooks because of their attractive layouts. Manybooks, on the other hand, does indeed have more file formats. So: Those are two important pluses for EACH choice.
Also, don't forget
MobileRead, as we have over 8,000 books at this time and growing rapidly.
I would also like to welcome you to MobileRead, even though you've posted about 7 times.
I always like to say this to pleasant personalities - Have Fun! 
Don