I haven't heard much about them in a long time either but even if I had I wouldn't be expecting anything significant. Meltdown affected Intel, IBM, and ARM processors while spectre affected any processor that used branch prediction up until that point. Both were patched the best they could be on all target platforms via combinations of microcode and kernel patches.
Significant class action suits tend to result from intentionally hidden and operated longstanding fraud or discrimination such as Enron or the tobacco settlements or Volkswagen. Even if Intel and every other manufacturer were found negligent for some part of spectre/meltdown it wasn't industry wide multi decade conspiracy to defraud.
I had expected these lawsuits to be significant, yet I haven’t heard much about them.