DnD Warlord
Adventurer
I didn’t object to anything (except kenders) my proposed solution is pretty simple though. So again we will just take orcs (but I think at least half the monster Manuel could get this treatment:Orcs have a base culture. It's just one you object to. What would you do different that would still give them a niche, make them worthy of an entry in the MM?
Orcs are on average strong and tough. Most are raised by a tribe. Enemy orcs could be a savage tribe, or an entire army breed for war, or just defending their own territory. Friendly orcs can be hunters who praise strength and nomads traveling to where they can find wealth. Any individual orc can be raised to think pretty freely. Often we use these as foot soldiers or savages but remember they each should have there own motivation. Presented below is a tribe of savages worshipping the god Grumish including half orc half ogers.
edit: add a side bar with 2-3 paragraphs of “orcs of ferun and Orcs of Eberon “