AKC Champion means the dog has earned it’s conformation championship through the AKC. CGC is an AKC Obedience title meaning “Canine Good Citizen”
GRCH means the dog has achieved it’s Grand Championship. This could be either AKC or UKC - usually people specify if it is UKC, but not always.
URO3 is a UKC Rally Obedience title (Level 3)
SHR is a UKC hunting title (Started Hunting Retriever)
CGC - same as above (Canine Good Citizen)
RA - AKC Rally title (Rally Advanced)
The other two are through the Lab Ret. Club - WC is a “working certificate” meaning the dog has demonstrated basic instincts in the field, and CC is a “ conformation certificate” meaning the dog adheres to the breed standard without any major disqualifications.