Every H-bridge has two "high side" and two "low side"
FETs (or other, but most commonly). An H-bridge driver
IC will control all 4 with some anti-shoot-through
goodness in most cases.
But a stepper motor has usually 4 phases (?) and
would need 2 H-bridges (if phase pairs, antiparallel
is the drive scheme) - 2 drivers, 8 FETs, plus odds
and ends like bootstrap caps one per leg, decoupling
and so on. Phase control happens upstream.
But this can all be found in integrated stepper motor
drivers, if you need less than maybe 5-10A per phase.
Integration slurps up the cost of the external FETs
and makes the total BOM cost cheaper for any
project that the part can handle.