Orcs were also in Giantslayer.While Giantslayer is well done, it´s not really spectacular or outstanding.
Old school is overrated, especially in the light of everyone understanding something different there, up to different genres and times. I just had a big discussion with some 50+ year old players about that term and for them it´s not about dungeons, dragons, giants or whatever, but more a style of play, mainly the absence of a clear plot and story. Instead the players are supposed to develop that somehow.
Something that should also not be forgotten are modules.
There´s several modules catering to stuff like orcs, dungeons, etc.
Unfortunately none for Tian Xia.
In the context of D&D, "old school" means a combination of:
- streamlined rulesets (no splatbooks),
- balance? what's balance?
- no weaboo wuxia anime video game 'fighter does anything apart swinging his/her sword' bull,
- strong GM control over the game (no magic items for you unless the adventure says so etc.),
- adventures focused on combat and dungeon crawling,
- strong adherence to genre tropes (Paladins must be LG, it's Orcs->Ogres->Giants->Dragons).
and it is far from overrated, given what runaway success 5e is with "old school" folks.