Higher CR "generic" enemies?

[Protato]

What do people use as generic bad guys after enemies like Orc, Goblins, and Kobolds stop being threats without a lot of support or strength in numbers? I was thinking of using Veterans as generic enemies for a party of L5. Mind you, I tend to allow a lot of shenangians (such as allowing a Monk with Light to cast it on their fist and get advantage, and allowing them to move up to 90ft. a turn without dashing due to abuse of polevaulting and the Jump spell) so that's part of why most CR 1/2 enemies pose practically no threat whatsoever.

[visitor]

At level 5, you can still get some mileage from those 'generic' bad guys. Orcs, Gnolls and Hobgoblins have minibosses and bosses of CR 2-6. Throw in a bunch of mixed support (ranged/melee), some traps and/or fun terrain, a friendly Ogre or three and there you go. A pet Troll is CR 5.

A Horned cult with priests, veterans, antipaladins and a whole bunch of Minotaurs.

Undead.

Lycanthropes range from CR 2-5

If you're going to let them slide on a lot, maybe you'll have to ramp it up to Giants. Start with Hill Giants and work your way up.

[CTurbo]

I really like slapping together NPC villains, and/or up-statting lower CR monsters by giving them more hp, higher AC, a bump in Str/Dex, extra attack, adding a feat, etc...

[Unoriginal]

Mind you, I tend to allow a lot of shenangians (such as allowing a Monk with Light to cast it on their fist and get advantage, and allowing them to move up to 90ft. a turn without dashing due to abuse of polevaulting and the Jump spell) so that's part of why most CR 1/2 enemies pose practically no threat whatsoever.

...pretty sure that's the main reason why enemies aren't much of a threat.

You should let generic enemies use crazy shenanigans, too. Suddenly they'll be much more relevant.

After all, it's not fun if only one side get to do it.

[Mad Max]

I adore the Gith, but they are lore heavy villains. Assuming you can re-flavor/re-skin enemies them, they might work. If you're thinking in terms of mercenaries or the army of a dark lord, there are plenty of minotaur, ogres and bugbears that you can throw against your party. Alternatively, to up the challenge for your party, try giving monsters class levels based on what they're up against.

For example, if the party is raiding a goblin warcamp, you could modify some of the gobbos thusly:
Hobgoblin Maglubiyet worshipper (Hobgoblin Paladin 2)
Goblin Maglubiyet worshipper (Goblin Cleric 2 (Trickery or Death))
Bugbear Devastator (Bugbear Barbarian 1)

I also love to give monsters magic items. Aside from just stat boosters, you could give them things like spell scrolls and wands, flametounge weapons, or healing potions.

Hope that helps!

[Afrodactyl]

You can also adapt the tactics your monsters use. Where the monsters may have gone for a 'meat grinder' approach with brute force when the party were third level, they need to fight smart now that they're twelfth.

Mix up the monster groups as well. I like to use giants (typically hill or frost) and ogres as mercenary races in my games. It's so much easier to keep humanoid enemies relevant when I can sprinkle some huge beaters into the mix. Them being mercenaries lets me muck about with their gear too. A frost giant with a Merrow's harpoon is suddenly a lot more dangerous when it can pull the wizard into squishing distance.

[Asmotherion]

I don't use generic enemies. I mean, I do use Goblins, and Kobolts, but that's it. Bounded Accuracy makes them relevant for the whole game, so if I need to use something like that, I just use more. Otherwise, I make a mini-boss fight.

I may manipulate the odds, braking the party so that each one of them will face a boss one on one, untill they come together again.

Or I may go for a Boss and 2-3 stated NPCs. I May build an NPC as a Boss as a Character of a Higher level than the PCs. Sometimes I may buff a lower CR monster into a boss fight by rising it in Character Levels (and thus HD), or giving it a Template.

But, I try to keep the "non important fodder casualties" feeling as minimal as possible. I want to enhance the feeling that everyone they meet is someone with a name, and even if they don't hear their name, he might have a fammily somewere.

I even described an orc Burial once, and a player found on the corpse being burned one of his arrows (they fought the previous day, and they were hunding for food at that moment, when they found the clan's camp and hid behind a bush; The Arrowhead was then put in the urn, as a Badge of Honour for falling in battle and not as a Coward. From that moment, the party respected the generic Orcs a bit more XD

[bc56]

Summoned fiends. Massive variety of CR, fun abilities, etc.
Also gives an excuse to use enemy warlocks.