Some of the infoboxes for Battle articles list Houses which possibly participated in a battle, along with Houses whose participation can be sourced. For instance, the "Battle of the Blackwater" mentions Houses Myatt (since the Myatts help escort Tywin's corpse back to the Rock in AFFC), Hayford (since they are in the crownlands), Leygood (since they are with Randyll Tarly in AFFC), and Penrose (since they are with Renly at Bitterbridge in ACOK). Regarding Bitterbridge, however, GRRM suggests here that while most of the men at Bitterbridge joined the Tyrell/Lannister army, some went home. House Peake is included among the Reach's men during the battle, but IIRC the Peakes haven't done anything so far in ASOIAF. There is fighting throughout central Westeros (almost as far north as near the Twins in early ACOK), so it's plausible some houses eventually rejoin Tywin or Randyll after regional campaigns or as reinforcements. To be on the safe side, I think it would be better to avoid assumptions and only list info which can be sourced.