I'm not exactly sure what the first one in the brass sleeve is for, I think you're probably right when you say it might be some kind of depth stop for it though.
The second lot look like power augers (round shank) or maybe old-style bit and brace augers with the square taper tangs cut off.
The third lot are a mixture of old-style bit and brace augers and maybe some power augers, the one with the modern hex shank is definitely a power auger.
As far as value is concerned I have no idea but some brands like Mathieson, Ridgway and Irwin are more desired amongst the old bit and brace fogies :lol: