As usual, Sunday is a big day for silent penultimate panels:
Cow and Boy by Mark Leiknes
Piranha Club by Bud Grace
Heart of the City by Mark Tatulli
Pearls Before Swine by Stephan Pastis
Mutts by Patrick McDonnell
Drabble is so lame, it can't even put its silent penultimate panel in the right place.
The rules committee has decided that the proper term for this is antepenultimate, as suggested in the comments a while back.
Today's Betty is a good example of how to build a comic pause without using a silent panel.
Instead, Delainey and Rasumussen use an extra-wide panel and place the word balloon in the right half of the panel. In this one panel, they create both a comic reveal and a comic beat. It's an efficient and snappy use of comics grammar. And efficient and snappy are two essential cells in the bloodstream of funny.