Off the Mark has generally been the best of the single-panel cartoons on my daily list for quite a while, and they’ve had particularly good ones for two days in a row now (the second one took me a moment). Comics Sherpa has always been a good source, with a funny though kind of icky entry from Whatever USA and Space is the Place today. Whatever USA is frequently updated and consistently high quality; Space is the Place has been pretty good, but is updated very infrequently. You have to love any comic that does this, though:

platypus panel