How could we level pets quicker?

depending on the pet level if ca vary, since after level 60 it takes longer (since the amount of exp needed to reach each subsequent level is significantly higher, lower level grinding areas don't really give them exp anymore, and exp orbs below lv61 can't be used on them, while orbs lv61+ are rarer and thus more expensive)

for lower level pets, DotF, and exp orbs

other than that, grinding in the fest zone, and being put on a team with higher level team members and taken to fest zone/lg

Is there another way is go to the groups, clubs and services and found the free pet leveling?

Just like this orb?

yes there are people who offer leveling services in the forums. How much they charge will depend on the person, the level you want your pet raised to, and how many levels that will take.

And yes that's an exp orb, as it says in its name and description (as you can tell, orbs tend to go for several tens of thousands apiece, since the only way to get them is the rare drop chance from enemies of the matching level)

How about making gold?

guide to making gold
guide to missions and mission pets