It can be very difficult, particularly with certain breeds/crosses, to find decent breeders who are going about things properly. Normally if you were looking for a specific breed you'd start by contacting the breed club who would be able to put you in touch with good breeders with litters planned. Whilst clubs do exist for some of the more popular crosses they seem to be far less discerning about their members, often having puppy farmers (albeit ones with a very nice facade) on their lists of recommended breeders.
What is you like about the two crosses you've mentioned?
If you're after a large, energetic, low shedding dog (bearing in mind that less shedding = more grooming) then I'd suggest looking at standard poodles. They're fantastic dogs; intelligent, trainable, genuinely low shedding and generally really good fun. They don't need any more grooming than a poodle cross, in fact they need less than some depending on the coat the cross inherits.
It's quite difficult to find breeders of crosses who are doing anything more than straight crosses of the two parent breeds which means there can be quite a lot of variation in the resulting puppies. If there's a particular type you're after then you really need to look for breeders who are specifically breeding for that type rather than just sticking a poodle and a lab together then hoping for the best.
Standard poodles, labs and goldens all need to be health tested for a number of different conditions prior to being bred and this still applies if they're being used to produce crosses. You can see lists of the relevant tests on these pages:
Standard Poodle
Golden Retriever
Labrador Retriever
Although some of the conditions that can be tested for aren't shared between the breeds that doesn't mean it's acceptable to skip those tests. It's very common for breeders of poodle crosses to not bother with the vWD test because the disease isn't present in the other breed they're using however it's possible for dogs who are only carriers for vWD to be affected (albeit mildly) by the disease.
In cases where a dog's parents have both been DNA tested clear for any condition it's then not necessary to perform that particular test because that dog can't be anything other than clear. In such a situation I'd expect the breeder to have copies of the relevant paperwork for the parent dogs for you to see.
This guide is obviously geared towards people looking for a pedigree puppy but a lot of it is still relevant anyway. Their list of questions to ask a breeder is also good and most of it is relevant regardless of whether you're looking for a pedigree or a cross.