The list is not in any intentional order. It begins with those you mentioned (with links added for convenience). Then a few more which have been mentioned from time to time on the forum. It is not an exhaustive list.

Each may offer a different type of in-person experience, and these may change over time.

Lists for "High IQ Societies" may be found by web searches, but these are, I believe, geared for adults, not necessarily for gifted children.