No such thing, purely because horses are all individuals and will always be capable of providing problems and depending on the capabilities of the rider/owner those problems will be manageable/acceptable or not.
The majority of dealers, even at the top end, will not have the horse long enough to thoroughly know it. A veneer of schooling/polishing will be done and the advert will be done.
Remember every day the dealer feeds the horse/pays the staff is a cost that has to be recovered via the sale, especially if the dealer is a low end yard trading in the cheap types.
That said, I would and have bought from dealers. One horse came from a very well known top end dressage dealer in Surrey and an high ticket horse. He was as described and had a good return policy included in the sale. It took him a year to settle into my tiny and peaceful yard (he had come from a 100 plus commercial yard). Ok, he won his first competition, but to handle he was a nightmare. The advert had said gentle and easy, which he is but it took a long time.
The second horse came via a private sale but had originated from the high profile cob dealers in Sussex. The cob was sold to a novice young man as a first horse aged 4 and said to be safe and quiet in all ways.
Of course it was quiet, a long trip on the boat, plenty of work on a young horse and out it went. Twelve months on it was back on the market as a private sale which I responded to. It was a bargy, opinionated thug which had terrified it's novice owner. It's mouth does not match it's passport, it would have barely been three when sold from the dealers yard. I have had it a year now and good progress has been made, the horse is safe and now has manners, which as a clyde x RID tank weighing in at 700kg it needs to have. I still would not sell it as suitable for a novice because it would not take long for it to revert into taking the p, even though it appears to be a dope on a rope.
So, OP, visit any dealer with an open mind. If you know what you are looking for you may just find a gem in the rough. Always take a second, experienced opinion with you and use a very good vet. Look beyond the advert and make sure you try the horse in every possible situation. Good luck.
Yew Tree Farm Irish Sport Horses - bought a cob from them who was best horse I've ever owned and kept him there on livery so saw a lot of other horses come in and be sold on - if you're looking for a competition horse they might have one in (usually only have two or three in at once) but they will also find you a nice cob or a connamara but you might have to wait a while - only thing is you won't get a cheap one!! They have a website.