At a time when Meta was Facebook, there were FANG (Facebook, Amazon, Netflix, Google) and FAANG (with Apple), but it seems to be more used in a finance context.
1. 100 IXes alone would get 56% IPv4 and 61% IPv6 prefixes, but ~14% reachability
2. little uniqueness between exchanges: not many new prefixes after the top 5
3. for outbound-heavy networks IXes are great, but to attract traffic they are not (edit: applies to automatic peering via route servers)