Warcraftpets dot com lists the most popular pets and where to get them. Check the AH as lots are really cheap. And as others have said I’d be happy to donate a few, for instance i have 3 Ikky which is a strong commonly used pet. You can use the pet battle tokens from BFA and SL to buy charms that will add 25 levels or raise quality to Blue. (There are no purple pets for you, only the tamers in game get epic and legendary pets but all are beatable). Keep us posted and have fun.