I've seen a similar idea applied on other petsites, but what if we had achievements that gave rewards based on how tough they are to complete? I know we have forum avatars which are kind of an achievement system in their own right but those could always be combined with this kind of thing! The highest rewards could be given for the harder achievements, like:
Hatching black, albino or achro CS
Hatching a coloured mythical
Hatching a mythical egg
Hatching any creatu in every possible colour
Hatching your first albino creatu
Morphing a wyrae
Completing a whole collection of creatu
Using an RSTU001, 002 and 003 frame
Hatching ivik, galta, and cyancu
Hatching one of each CS egg
Hatching one of each seasonal egg
Reaching TU milestones like 50 mil, 100 mil, 500 mil, 1 bil, etc.
Winning top 50, top 25 and top 10 on leaderboards
Completing Kir's quest
Evolving each type of iubui
Hatching feiron, viarindi, cetari and guilbyss
Completing a certain number of collections
Reaching certain intellect levels once with one pet
Unlocking a certain number of forum avatars
Hatching one of every creatu...
And so on! Just site goals that are hard to complete, but they could offer cool rewards. More minor rewards could be offered for smaller achievements such as:
Completing an event quest (this is already kind of a thing since we have trophies and such but like... combine it)
Reaching enough reputation to get a blessing
Playing each of the planet games once
Making a sale in your merchant and rancher shops
Having an egg fail at 100% (like "wow that sucks here's an achievement" lol)
Hatching a mutant
Reaching each tier in the enchanted springs
Completing regular quests (excluding Kir)
Buying and selling stocks
Zapping a creatu with a regression ray
Hatching each creatu colour (excluding natural; blonde, calico, albino and achro offer higher rewards)
Getting a colour change from the springs
Finding a quelis egg in the springs
Adopting an abandoned pet from the atqueen forest
Sending a certain amount of rmails
Posting a blog
Editing your profile code...
And whatever else we can think of. I just figured an achievement system might help even more with keeping people interested in playing! We don't necessarily need one, but I figured I'd suggest it anyway c: