I'm partial to "MAGA" as the initialism for the top 4 tech companies by market cap (Microsoft, Amazon, Google, Apple). Facebook and Netflix are a tier below in market cap and size, and it also makes it clear who's really making America great again...
I've seen GAFAM a lot, and that's the one I tend to favor.
MAFANG (maybe?) if you really want to get Netflix in there? I know some people especially in the Bay Area think Netflix is important in the acronym not necessarily by market cap, but overall head count versus turnover and thus cultural swing (policies like "unlimited vacation" that started at Netflix and then in turn influenced a lot of other surrounding Bay Area companies).
I don't think this is true. Actually, most people would like to replace "N" with "M" in that acronym, but then it sounds much worse…