## Raticate ##
Raticate is really meh. Looking at its possible abilities, Hustle and Guts stand out as good abilities for physical attackers. However, it has pathetic stats holding it back, with no stat standing out barring for a decent 97 base speed backed up by 80 base attack. Throwing a look at its movepool, Raticate gets pretty colorful viable attacks on it like Sucker Punch, Wild Charge, U-Turn, Ice Fang, Flame Wheel, Return, Iron Tail, Zen Headbutt or Reversal. These options look appealing, but they won't do a lot of damage from a basic rat with passable stats.
In short, avoid Raticate.
Possible Moveset:
Youngster Joey (Raticate) @ Choice Band
Trait: Hustle
EVs: 252 Atk / 252 Spe / 4 SpD
Adamant / Jolly Nature
- Return
- U-Turn
- Wild Charge
- Crunch
Other acceptable moves: Flame Wheel, Ice Fang, Reversal, Sucker Punch
This set is designed to be as hard-hitting as possible. A Choice Band, Hustle, STAB Return hits hard, no matter what. Raticate is going to leave a fissure into even sturdier Pokemon. But this set is outclassed as other Pokemon can do it better.
Other options to consider: Life Orb, Super Fang, Guts, Sleep Talk
## Furret ##
Furret is even worse than Raticate. It may sport a better bulk than wet-paper rat sturdiness but nothing, nothing helps this furret. From its middling 76 / 90 offensive stats to a lesser appealing movepool, Furret doesn't have anything over any rodent that could put it to any use. I may like Furret a lot but that doesn't justify I'm going to rate it for what it doesn't stand for.
In short, don't use Furret at all.
Possible moveset:
Literally useless (Furret) @ Choice Scarf
Trait: Frisk
EVs: 252 Atk / 252 Spe / 4 SpD
Jolly Nature
- Trick
- Fire Punch
- Return
- U-Turn
This makes for an acceptable scout in the lowest tiers. Trick can cripple defensive Pokemon to no end; Ferrothorn will miss stacking hazards, Chansey will miss walling with Toxic + Softboiled and I could go on. Attacking moves are here to decorate as Furret has even less power than Pignite, a non-fully-evolved Pokemon.
Other Options: Unfortunately nothing. Furret is a good-to-nothing.
## Linoone ##
Finally a good rodent. Linoone is a great Pokemon. Overshadowed, sure, but it's great. I like it, but there's a reason to why it's good compared to the two others aforementioned. It has less attack than even the weak furret and less bulk than Raticate, but it's the speediest of them two, and gets 2 moves any rodent would dream of: Belly Drum and ExtremeSpeed. Oh, and its movepool is acceptable, albeit less extensive than Raticate's.
In short, you should try Linoone.
Arceus maybe(Linoone) @ Sitrus Berry
Trait: Gluttony / Quick Feet
EVs: 252 Atk / 252 Spe / 4 SpD
Adamant / Jolly Nature
- Belly Drum
- ExtremeSpeed
- Shadow Claw
- Seed Bomb
Remember E-Killer from Ubers? Linoone is kind of E-Killer in lower tiers. It can insta-sweep unprepared teams. Adamant could easily be used with Quick Feet and even without it because you'll be spamming ExtremeSpeed unless you come by a Ghost-type. Seed Bomb is decorative actually. Gluttony will make you eat the Sitrus Berry as soon as possible, but it's not very functional. Quick Feet allows you to come on a predicted Toxic and grab some speed.
Other Options: Use Linoone as an in-game slave for HM; Surf, Rock Smash, Strength and Cut.
## Bibarel ##
Bibarel is a very meh Pokemon. It has less offensive presence than any of the rodents with its bad speed compared to those speedster above it, and less attack than Raticate or BD Linoone. But it stands out with excellent abilities. Sadly, it can't use them adequately for it isn't backed up by anything stellar, and Moody is banned in Competitive gaming. Nothing stops you to use Moody in Anything Goes though; it's really worth a shot.
In short, don't underestimate Bibarel.
Possible Moveset:
HM Slave (Bibarel) @ Leftovers
Trait: Simple
EVs: 252 HP / 252 Atk / 4 SpD
Brave Nature
- Curse
- Waterfall
- Return
- Quick Attack
Since Water/Normal has amazing neutral coverage together, you won't really need coverage moves. Curse will double its Attack and Defense stat at once with Simple, but will lower its already low speed to very low levels. Quick Attack can patch this up, especially if you need to pick up a weakened foe. Return and Waterfall are your go-to STAB options.
Other Options: Use Bibarel as a slave; it learns every HM barring Fly. If you want to use it competitively with something else than Curse, try Moody in Anything Goes or Unaware if you feel like it; but Simple is the best for standard Competitive gaming.
## Watchog ##
His eyes. Are your brains on drugs. On a serious note, easily the worst of rodents. Please, don't use Watchog. Bad offensive stats, weak bulk. Heck, it's very slow too. There's nothing Watchog can do and that other rodents can't do... except maybe. Well nothing.
In short, Watchog is the worst rodent, you MUST avoid it at all costs.
Possible Moveset: Nothing. It can't freaking pull off any good moveset. Except to be an annoyance against Team Plasma and Lenora with Hypnosis + Confuse Ray.
## Diggersby ##
Oh, my good goodness. This is your bunny on drugs. No, let's be real now: Diggersby is an excellent Pokemon to use. It's even banned from UU! It's the only Rodent that made it that far. And for good reasons. Unlike Linoone which could be better, it has acceptable bulk of 85 / 77 / 77, which makes it pretty hard to take down with non-SE attacks. Then, while it only has 56 base attack, it gets Huge Power. I'm looking at Azumarill right now; it also has Huge Power, and that's why it's in OU, its typing apart. And finally, it can patch up its poor speed with a Scarf.
In short, Diggersby is easily the best rodent.
Possible Set:
Diggersby @ Choice Band / Choice Scarf
Trait: Huge Power
EVs: 252 Atk / 252 Spe / 4 SpD
Jolly / Adamant Nature
- Earthquake
- Return
- Ice Punch
- Knock Off
It also gets Fire Punch and ThunderPunch, U-Turn, Bounce (lol why), Gunk Shot and Superpower. Very colorful pool. Diggersby is a great scout with U-Turn, outclassing Furret; it also beats Raticate with its STAB Earthquake whilst Raticate is only purely normal; and Bibarel and Linoone don't compare because these are setup sweepers.
TL;DR: In order:
- Diggersby
- Linoone
- Bibarel
- Raticate
- Furret
- Watchog
Bibarel and Raticate are very disputed actually. But I give mention to Bibarel's usefulness in-game too, whilst Raticate is Youngster Joey's mate, the first trainer you ever meet (correct me if I'm wrong). I hope this helps you choosing your rodent! ;)