I'm seeing test clips like this:
Which are for SOIC packages (lead pitch 1.27mm). If I had one of these for (two edges of) a TQFP package with lead pitch 0.8mm, I could make a clip-on serial port for the ATmega328p. It would still need a separate ground clip but an alligator clip would do.
I'm aware of "Delta probes", but they are way overkill and expensive, and they aren't available for a 32-pin TQFP anyway.