My growing collection of rpis includes an rpi2 with a usb wifi dongle that still gets a fair amount of use. Mostly for experiments, but truth be told, it's not an old slouch.

These pi models are all tailor-made options. I think its a mistake to think in terms of "older models" when you consider the lower power requirement and higher physical stability of the rpi2 (doesn't overheat even without a fan, for example). The Zeros are less powerful but still belong in the range because of exactly that.