Oh third generation what a magnificent/weird generation it brought titans like metagross, salamence, and even legendaries like latias. However with such talent, there had to be a couple of pokes that drew the short end of the stick, introducing Delcatty. With no base stats over 70, normal typing, and many other pokemon that can do its job, Delcatyy has a hard enough life. Now it does have a unique ability, but even that ability can't help it, neither can it's amazing movepool. If gamefreak would have given more stats, maybe Delcatty could do something, but honestly, this poke is going to have to prove a lot to you to earn a spot on your team.
Normal?
Ability: Normalize
Item: Leftovers
Jolly Nature
252 spd 252 hp 4 def
-Thunder Wave/Toxic
-Toxic/Thunder Wave/Sing
-Heal Bell/Sucker Punch/Double Edge
-Wish
Now Delcatty can do more than just support, but with it's awful stats, I'm trying to focus on it's amazing support movepool, and it's ground breaking ability. Normalize is a odd ability, making absolutely everything STAB, but with no coverage, and ghosts are not effected by anything you do. However, being able to paralyze a ground type, or poison a steel or poison type is nothing to mock at. Unfortunately ghosts ruin this set, but thats why you need support. The first to slots are for status and your choices are:Thunder Wave is obvious and can help Delcatty be faster to do more support for your team. Toxic is fun to play around with, and is a good second choice status move. Last is Sing, but with 55 accuracy, it's shakey, and toxic might be more reliable. Now since Delcatty won't be hurting anything, many feel there's no use in putting an attacking move on it, so Heal Bell is nice for removing statuses from your team. However, if you get hit with a taunt this set is done for, which is why you can use sucker punch for priority, or double edge for power, and because your attack is so low, the recoil will be easily recovered. Wish is simply for some type of healing. Leftovers is for some minimal gain, and the EV's, and nature allow you to maximize HP, and speed which is all Delcatty actually has.
Run Cat Run
Ability: Cute Charm
Item: Leftovers
Jolly/Modest Nature
252 hp 252 spd 4 sp atk/172 hp/176 sp atk/160 spd
-Baton Pass
-Substitute/Protect
-Charge Beam/Wish
-Calm Mind/Wish
Now Delcatty may not be the most trust worthy Baton Passer, but she can do this decently, and this set will probably be the most likely set to be used. Being able to combine sub, calm mind, and charge beam is special, and makes for a decent special passer. Baton Pass is for of course, for passing your boosts. Substitute is useful if you get one up, but you might not have the chance, so Protect is nice to get some leftovers recovery. Charge beam has a good chance of getting a special attack boost, and it is an attack. But Wish has support, and healing all in one. The last slot is for calm mind, which helps you take a special attack, and increases charge beams power if you decide to use it. With Cute Charm as your ability, you might get a physical attacker stuck, which will allow you to set up. The nature is for speed, or power, and the EV's allow you to out run some guys, however, if you want more sp atk power go with the second set of EV's. If you decide to not use Charge Beam, use Jolly and the first set of EV's, if you do use it, Modest and the second set of EV's might help Delcatty to do some damage.
Dellead
Ability: Cute Charm
Item: Focus Sash/Life Orb
Jolly/Adamant Nature
252 atk 252 spd 4 hp
-Fake Out
-Sucker Punch
-Thunder Wave/Toxic/Sing
-Baton Pass/Assist
Now after 2 sets am I finally going to share with you an attacking Delcatty. Having Fake Out already describes a lead, and with decent support moves, a good priority, and a crazy filler move you might have a decent lead. But the stats are just plain bad, and really hinder this sets potential. Fake Out is obvious, as it hits them for some damage, and flinches, which allows you to decide whether you want to stay in, or switch. Sucker Punch gives coverage on ghosts, and has priority, and has pretty good attack power, so it's an obvious choice. Thunder Wave makes Delcatty a lot faster, and disrupts your enemies lead potential, where Toxic is good for crippling a defensive lead trying to set up entry hazards, and Sing is just for a lucky sleep inducer, which could be really awesome if you pull it off. Baton Pass allows some scouting, but assist is a funny move that could end up getting you a crazy fire stone edge from your sweeper. Only use Assist if your team has a lot of crazy sweepers. Cute Charm again, can get you a lucky immobilize, without using attract. The Nature is either for speed with Jolly, or attack with Adamant. The EV's allow max speed and attack, which is good for a fragile pokemon, with pretty bad attacks. The item is either for power with life orb, or survival with focus sash.
Delcatty definitely got screwed in the stat department, however, it did get a lot of useful support tools, and maybe, just maybe, if they would have given this poke some better stats, he might be more used. Of course this POTW is going to need support from your other party pokemon. Having strong special and physical walls allow some nice switches, and support for the fragile Delcatty. For the lead set, and the baton pass set, both need a speedy sweeper to come in and take out the trash, but for the baton pass set you need a special sweeper, where as the lead doesn't really care. And finally for the Normalize set, something that can hurt ghost types, because after the enemy knows your running normalize they will switch in their ghost in a heartbeat. Ghosts work well for hurting other ghosts, cause chances are they will try and either status you or fighting attack you, which is easy to get rid of for ghosts. There are a lot of counters for Delcatty, but most importantly it's steel/rock/ghosts types that are going to give you some trouble.