Are there any analog building blocks available? Basic stuff like bandgaps, bias cells, opamps, power management ldos?

There are a handful of them that were created with the initial tapeout designs; they will be a bit hard to find if the designers don't tell you about them. At some point I (or somebody) will organize what we have so that I can at least start building up an analog IP library that can be installed with open_pdks.

Our students had designed some (most of them in osu180 and few in sky130) You might want to take a look at them https://www.vlsisystemdesign.com/ip/ Our current batch of interns are porting most or all of above in sky130

Thanks so far.