So, with the size of the userbase it gets kinda chaotic! We're too small to have a consistent market for most ranges like FR, but the game isn't new enough that just anything is worth more than the fodder floor either (or less-- if (general, no necessarily OP) you're selling wolves for under 1,000 pebbles on the FM-- which is the base release price of a level 1 wolf-- and wondering why they consistently get bought and insta-released, it's probably people just releasing them for the minimal profit, especially if it's during one of the 4 pack holidays where they get a ticket on top of it).
Wolf prices would stabilize more if it was easier to relist on the FM, right now you can sell the same wolves from the same litters for both fodder floor & double digit MS prices just based on the chaos of when you list and if the right buyer sees 'em. :P
There are a lot of poorly-explored colorways, patterns, etc. that I'm honestly pretty surprised are still as uncommon as they are, but the ones you see on the FM are still floating around being mostly related to each other. Some of these guys still get snatched up when I list my offerings every so often at almost any price I care to list them at, because it seems like there just aren't that many people who list them for sale. There might be value in creating new bloodlines for some of those colors, but then again it can be a lot of den space & waiting games that people may not have the patience for, without the guarantee of new interest. Maybe that color combo is just genuinely niche, and there really are only 2-3 users interested in it. Maybe nobody wants to put the time into slapping wolves together to make more of them, but would buy them if they existed as an already complete project. No telling 'til you try!
Even most WWs aren't worth a ton, since they are by & large Deeply Unfortunate to behold and mostly just good for starting breeding projects.
Some things that warrant at least a second glance / paying attention to so you don't get scammed out of a potentially valuable wolf include low ID numbers, special ID numbers that refer to dates or are things like palindromes (number reads the same forwards & back), especially matchy WWs / some WWs that are doubles, but not all are cute enough that matters... Generation outside of 1 rarely matters outside of extremely niche collectors, and sometimes g2 bracs, since g1 bracs are artificially limited by the KS scrolls.
None of those are necessarily guarantees or anything, I've seen some g2 brac auctions get no traction but last day pings and no actual bids, sometimes not even starting bids. :P But it's a starting point, and good for someone just getting back into things that might have some old wolves that certain collectors might want.
But I also advise not taking anyone in particular's advice and go snooping yourself where you can. The forums aren't the absolute best for this, I've found a subset of people don't wanna make deals on the forums. There's also a few unofficial discords that this same information gets locked up inside of, but joining and searching their chat archives can be really... illuminating! about some of the pricing discrepancies that exist. ;)
Ultimately, good luck! Trust your gut, don't get got. If something you are looking to sell is a truly limited resource, like low IDs, it might be worth it to just sit on it for a while until you're more comfortable with the pulse of the limited market, rather than go into a deal you may not be happy with later once you have more information.
"Once again I have to bear the burden of having every correct opinion in the world."
