Firstly, welcome back!
With pets your best choice depends on what you're going to hunt these days, so I still keep and use older pets alongside the newer ones. I still have my first WW's, dragons and nightmares but they have got some different hunting partners now
What I've added to (and kept) are pets like the rune beetle, bake kitsune, greater hiryu and some novelty pets like my pack of cats and such. And a couple of dread warhorses.
You'll hear a lot about greater dragons and dread warhorses as those are the current "in" pets.
Dreads are currently not spawning and we don't know for certain if they ever will. It's quite possible that they won't. Which means you'll find most selling for millions of gps
I do like mine, but I wouldn't pay that much for one, because you're paying a lot for the rarity (possibly temporary) when the pet itself isn't essential for a tamer. They're nice, but I wouldn't go
that crazy over them. I'm still hoping they respawn heh.
Greater dragons are the beefed up dragon, and you'll see most tamers running around with one just now. They're very powerful and if you want a pet that takes minimal healing to kill spawn easily they're perfect. They're strong as tanks and good on damage so they make life very easy
I find their power makes them boring to hunt with so I don't use them.
My favourite pet is the bake kitsune, as you can have 2 and a 1 slot mount and they have good resistances and a strong attack. And they giggle lol. They only require 85 skill in taming and lore to control, but don't let that fool you into thinking they're a newbie's pet.
Cu sidhe are good tanking pets and they're big rideable dogs. They can heal themselves and their owners and they have a lot of hit points. The downside is they don't do a high amount of damage so you might find they're not ideal in every situation. Often tamers will use them teamed up with another tamer and their pets. The cu takes the brunt of the foe's attack while the other tamer's pets can safely attack a monster they'd likely die to.
Hiryu I tend to use instead of a cu, because they do more damage as well as being quite a sturdy pet.
Hope that helps you out a bit, but if you have any questions, you're in the right place
Wenchy