My pick is Venomoth. I've been using him with a custom EV spread, and he's been a great QuiverPasser, and Tinted Lens allows him to clean up in a pinch as well. I've been pairing him up with an Expert Belt Hydreigon (with Dragon Pulse/Dark Pulse/Surf/Flamethrower for wide super effective coverage), and it's been working quite well, because the opponent is a lot less likely to fire off choiced Fighting attacks against Venomoth, who 4x resists Fighting, making it a safer pass to Hydreigon.
The Venomoth set I've been using is the following:
Venomoth @ Black Sludge
EVs: 56 HP / 208 SpD / 244 Spe
Timid Nature
Ability: Tinted Lens
- Quiver Dance
- Sleep Powder
- Baton Pass
- Bug Buzz
Basically, this EV spread gives him just enough special defensive capability to stomach a Specs Politoed Hydro Pump after a Quiver Dance (or survive a Scarf Politoed Hydro Pump at +0 and set up while it hits you). Just for reference:
252+ SpA Choice Specs Politoed Hydro Pump vs. +1 56 HP / 208 SpD Venomoth in rain: 249-294 (84.4 - 99.66%) -- guaranteed 2HKO
This is one of the most powerful special attacks in the tier, so with this EV spread, Venomoth can set up against a very wide selection of special attackers (getting at least 1 Quiver Dance), and proceed to pass his boosts to the receiver quite easily. Before I tried this Venomoth, I tried punching in several EV spreads to try and get more HP in to take physical hits a little better while keeping as much Speed as possible (while still retaining the condition that he be guaranteed to survive SpecsToed Hydro Pump in the rain). This was the best spread I came up with, and I find that even though it doesn't have 306 Speed to tie with other base 90s, it doesn't usually matter in the end, because it can usually outspeed everything after 2 Quiver Dances, which are surprisingly easy to get. I also haven't missed the extra physical defense from the higher HP in the analysis' suggested EV spread, because it was never going to be setting up very well on physical attacks anyway. The only physical attacks he's setting up on are choiced Fighting attacks, and that's only because of a 4x resist.
Another thing that makes Venomoth a great QuiverPasser is Sleep Powder. You have the chance to potentially screw over your opponent's only chance of stopping the pass, and maybe get even more Quiver Dances in the process.
One other thing is that Tinted Lens is much better than Wonder Skin. I've very rarely seen people try to phaze out Venomoth to get rid of the boosts, which is the main case in which Wonder Skin would be helpful. Quite frankly, most people just try to kill the thing before it can pass, which Wonder Skin is not going to help against. While Venomoth is not a sweeper, Tinted Lens is extremely helpful when it's inconvenient to pass, and you already have a few boosts. Things like Terrakion, Keldeo, and Landorus-T all get 2HKOed by a +1 Bug Buzz after Tinted Lens, but barely even get dented if you have Wonder Skin. Whereas, Wonder Skin is only really protecting you against phazing, which isn't even going to matter if they just phaze on the turn you pass, and isn't going to help if they just decide to try and kill Venomoth.