Orcs, undead, and aberrations (The Far Realm type, not flumphs) have always been my mainstays. Undead are easy - and no "undead babies" issues - and things that want to eat your brain are pretty clearly "bad guys". Orcs due to LotR and literal decades of lore and novels and games. And in the back pocket are always demons and devils.
Having said all that, my current campaign I decided to try something different - as people on the first page of this thread suggested - and went a different direction. First - while there will occasionally be "animated corpses" for one reason or another, there are no "undead". (the current druid Witch the party is fighting has Circle of Spores-style plant-zombie-things, for example.) Second - the "crystal sphere" is closed: no far realms, no Lower (or Higher) Planes interference.
Third - and on point for the conversation - there are no orcs in this world. Replacing them are "The Tribes", a loose confederation of all "goblinoids" that unitedly hate the Invaders (the PHB races, aka Kingsfolk, confined to a corner of the main continent), but also frequently don't like each other. Primal / Nature / Spirit magic is the tool and trademark of the Tribes, while the Kingsfolk have access to Arcane and Divine. [Yes, PCs can be special and still be rangers and druids, but with story consequences; likewise, the NPC hobgoblin wizard is a unique and odd thing.]
And here's the thing - the Tribes aren't evil. They absolutely are "antagonistic"! But it's able to nuanced and worked with. The Tribes staged a war against dwarven mining concerns in the "neutral zone", with the intent to wipe out all the dwarves and steal their (superior) mines and forges. They actually won, briefly, despite the party's best efforts, but were pushed back after a few months. During the victory, a PC was captured (well, slain, revivified, and then interrogated), but made "friends" with the aforementioned hobgoblin wizard who was in the Tribal vanguard. Later, when the rest of the PC broke the occupation force (with hundreds of dwarven reinforcements), the captured PC saved the wizard's life. And then the entire party went on a long side-quest into Tribal lands, escorted by the hobgoblin! Along the way they cleansed a goblin village of invading Wisps, saved another village from a displacer beast that had moved into their woods (Legendary Boss), one character got training on how to be a shaman (multiclass'd into druid), and they rested and relaxed ("mandatory training downtime") for a week with the goblins.
And later, elsewhere, mercilessly slaughtered several bands of goblins that had massacred a successful farmstead colony in the neutral zone.
Heck, there is even an honest-to-badness rule-breaking true undead in the game (for Story reasons, despite the campaign limit) - and the party is working with and for him!
The campaign seems to be working just fine without "evil in the DNA" creatures.