The question is pretty weird and was the reason didn't get much attention.
We don't know of any good consultants. Besides they can't do any thing beyond filling forms and submitting applications on your behalf that you can do yourself if you are educated, can read / write and follow instructions.
Work permit requires an LMO which requires a job offer from a Canadian employer. This is a tough task to achieve while sitting in Pakistan and the reasons involve possessing some skills which are hard to find in Canada.
It is true that some consultants have made fake or some what companies in Canada and try to get people from here on supposed LMO's by charging those people a lot of money. Please be informed that
a. Government of Canada has toughen the work visa process and it is more difficult to do so now.
b. There is a very active chance of fraud in this situation - so better think twice before paying some one a lot of money for this.
c. Even if they do get you in Canada, it likely wouldn't be a very practical living job. So you really need to look if that is worth the effort and cost i.e. going to Canada, barely doing a hand to mouth job, bearing extreme weather and language differences. Is it all worth? Can't you make good enough money in Pakistan?
I am sorry if i sound harsh, but there is no formal standing of consultants. If there was, then CIC would have officially supported so. You should rather sharpen your skills and apply to real jobs posted online in Canada to get through those. If you can't then better way is to save a lot of money and meanwhile apply for permanent immigration.
