My recommendation is to look in the Trader's Hall and see what the mare and WW are being sold for, also the Prepatch old Bake-Kitsunes. Prices change but Prepatch (PP)
White Wyrms are very high value range from 150-250 M or even more depending on stats, and if "Heirloom" likely worth
billions to certain collectors, depending on rarity. The PP
nightmares are extremely valuable pets, esp to PVP folks, range from 100 M to 180-200 M also depending on stats. Tthe PP
Bakes range from 50-100 M.
You need to search the Trading Hall for most recent prices of these, you need to determine whether the WWs are "Heirloom" check to see if they eat gold, or if they growl or grunt when commanded. There is a post on these legacy WWs in Stratics, check it out. The PP Mares and PP Bakes also research the forum for pricing nowdays. The 3 slot dragons are iffy, may be bugged to slot-jump as soon as you start "training" them, not too sure.
A word or two of advice:
Gest estimates of their pricing in the forum here and don't believe in-game estimates for now at least.
Do not "train" the PP WW, PP mares or PP Bakes at all unless you train 2-3 other pets like Cus etc. Otherwise they lose massive value, & get ruined.
Would recommend selling in here if need to sell, and get bids for them here.
Don't hurry selling them, take your time.
The other ones have no value basically other than sentimental value, and their main job is to take space in your stable.
I hope this helps a little, sounds like you need to do a little searching but it is worth it.
Good luck and welcome back.