Those are various chipsets for Intel processors.
The simplest way to look at it is to break them now by letter and number.
B represents their business series, relative cheap not many features.
H is their locked chipsets, for those who dont OC.
Z is their overclocking motherboards.
The numbers refer to the various reiterations and refreshes.
At this point in time, all I would bother with are H97 boards if using locked processors, or Z97 for overclocking.