Pears are moving towards more size controlling rootstocks.

The Old Home X Farmingdale rootstocks continue to be the mainstay.

Listed in approximate order of dwarfing / size control--- results can vary with your site and the vigor of grafted scion.

PyroDwarf® (USPP 11041) [40-50%]--- Very precocious with fruiting beginning in 2-4 years.  High yield efficiency.  Uniform fruit size.  Highly frost hardy.  Does not sucker.  Low availability of varieties--- recommended for testing.
OHxF 333 [50-70%]--- A superior selection to replace Province Quince as it is much more hardy.  50-70% of standard size.  Resistant to fire blight and pear decline.  Does not sucker.  Well anchored and productive.  Does well on a variety of soils.  Some question as to its productiveness compared to other, more vigorous OHxF clones.   Very limited in availability and recommended for backyard planting only
Pyro™ 2-33 (USPP 12771) [85-90%]--- A very precocious rootstock recommended for testing at this time.  Early fruiting.  Shows good winter hardiness and anchorage.  Low availability of varieties--- recommended for testing.
OHxF 87™ (USPP 6362) [85-90%]--- One of the most precocious OHxF rootstocks.  Promotes early spurring.  Slightly dwarfer than OHxF 97.  Becoming the more preferred OHxF rootstock at this time.  Good availability of many varieties.
OHxF 97 [95-100%]--- This Old Home x Farmingdale selection is replacing common pear seedling.  Similar in vigor and size control it will produce almost standard trees which are very productive.  Well anchored.  Excellent availability of most varieties.
Pyrus communis "Bartlett seedling" [100%]--- Common pear seedlings which produce 100% standard size trees.  Being replaced by the OHxF series.  P. communis is very vigorous and has good productivity, but can be more variable than desired due to its seedling nature and natural genetic variability.  Reduced availability since being replaced by OHxF rootstocks which produce more uniform trees.
Pyrus betulafolia [100%]--- An excellent rootstock for Asian Pears on the East Coast.  Limited Availability.