There are many types of Giants in the Marvel Universe, and several of them dwell in the Ten Realms of Asgardian cosmology (and especially in Jotunheim and Niffleheim). They are sometimes similar in appearance, but there are more or less subtle differences.
Giants from South and Central America (and related realms)
Sleeping Giants
Giants from Europe and Asia (and related realms)
others
Mist Giants
See also Giant-Man and Giant-Girl