Shuckle
Pros:
- Access to both Sticky Web and Stealth Rock
- some support moves such as Encore, Toxic, Knock Off, Infestation
- Good bulky on both defenses
Cons:
- Slow as ****
- Quite passive if Encore is not used in the right place
- Basically complete Taunt Bait (unless Mental Herb)
Smeargle
Pros:
- Access to every single move including Sticky Web and Stealth Rock
- Access to support moves like Spore, Nuzzle, Rapid Spin, Taunt, Magic Coat
- Fairly fast
- Can also Baton Pass boosts
Cons:
- Very low defenses
- Pokemon with Substitute and Taunt can take advantage of it
- Basically forced to run Focus Sash
- Still outsped by much of the meta
The above two are the main ones for National Dex AG. Each of then have their pros and cons, and it's basically your choice if you want a somewhat fast setter or a bulkier one that can still annoy the opponent to hell with Knock Off and Encore. Other setters are generally worse than Smeargle and / or Shuckle, but here are some honorable mentions:
Ribombee
Pros:
- Access to support moves like Stun Spore and U-turn
- Is the fastest Sticky Web user
- Can still be somewhat of an offensive threat with Moonblast (but not really)
Cons:
- Mainly still outclassed by Smeargle
- Has pretty terrible bulk
- Must run Focus Sash
Galvantula
Pros:
- Access to compound eyes + Thunder Wave that always hits
- Access to support moves such as Thunder Wave, Toxic, Volt Switch
- Very fast
- Can pose an offensive threat to things like Kyogre with Thunder
Cons:
- Pretty bad bulk
- Still outclassed by Smeargle usually
- Must run Focus Sash
So yeah, the main ones in NatDexAG are Shuckle and Smeargle but if you want to spice things up you can also use Galvantula or Ribombee as an alternative. Personally, I would recommend just using Shuckle or Smeargle just because they're a lot more useful in general. Hope I helped :)