This is a really good overview of some features that are common in enterprise SaaS, but I would caution against thinking that they're necessary to be successful in enterprise SaaS.* My experience has been that if you have a really compelling core feature set, most everything else is negotiable. Some are nice to have, some are regulatory, and some are just something someone added to a list because they thought it sounded like a good idea. Even the ones you do decide to implement, make sure you do enough customer discovery to figure out how it relates to your market.
* Except security. Always be thinking about security.