There's Calico, CapitalG, Fiber, GV, Intrinsic, Isomorphic, Verily, Waymo, Wing, X. Nest and DeepMind were absorbed into Google, and many of the previous Alphabet mini-companies are already gone (Makani, etc).
My personal expectation is that Calico will eventually wind down, as their research has been pretty unexceptional and I don't think they've managed to find any real revenue sources.
Intrinsic is probably on borrowed time, looking for revenue, and if they don't get significant amounts in the next two years, will be shut down.
Waymo isn't profitable yet but it looks like the execs have decided to give it a very, very long runway, and they are the technical leader in no-driver cars. It's still at risk if they don't find a good revenue model.
Wing has no real revenue to support their costs, and drone deliveries just aren't going to be a great business, so I expect it to shut down in the next two years.
Fiber- it's hard to tell why Google has allowed this to continue for so long. The only thing I can imagine is that they are somehow using the usage data to generate revenue or ML training data.
Intrinsic is really new so they probably have a couple years runway, but pharma sales aren't a great business to be in if your only product is a protein structure predictor and binding predictor. I work in this field and I still see this as an unrealistic bet on Alphabet's part.
That leaves Verily. It's clear Alphabet has downsized it significantly and scoped the projects down significantly. They have turned away from every single early idea and pivoted to a few remaining areas where they have some strength. I work in this field and it's amazing to me they keep it around- so I expect that unless they sell it in the next year or two, it will be shut down.
CapitalG, GV, and Google's real estate ventures will probably all continue because they have generated a fair amount of revenue.
Google Cloud is part of Google, not Alphabet, which IMHO is an insult to the people who run it. It could be spun off as an all-in Alphabet company but it's so closely tied to the rest of the Google infrastructure it will never live on its own.
Truly impressive how little Alphabet has achieved.