There is no hard limit, but many components bring additional dependencies which obviously affects the resulting size of the distribution package. For example, the Full-Text Search add-on depends on a bunch of heavy parsing libraries and increases the WAR by several tens of megabytes.
Also, add-ons may in theory interfere with each other if they extend or override underlying framework mechanisms.
So I would recommend including only add-ons that you really need, and after thorough testing them with your application.