The real estate bubble is still going on in some countries, and housing prices have absolutely gone berserk again after the recovery from 2008. If this trend continues, it could potentially brew up into something huge again. Hopefully though that the adjustment comes sooner than later so that the consequences of this real estate bubble v2 isn't as big as the GFC.

A lot of people are saying that crypto is the next big bubble, but honestly it's just the natural cycle of bullishness and bearishness that went on in BTC ever since that it was first traded. That boom/bust cycle has always existed, and the extent or the potential damage of which is probably much lesser than the other bubbles, like real estate. Really depends on how you view the word "bubble".

Bonds can definitely be in a big bubble right now as well, Greenspan himself said so.