Did you know any available quotas for foreigners

No quota for foreigners. Those jobs where Singaporean won’t take such as construction labourers, waiters, domestic helpers, washroom cleaners etc, companies hire people from mostly underdeveloped or poor countries as cheap labourers. These people live and work here in a bad situation and underpaid (with few hundred dollars).

There are no quotas for sectors (as in groups of companies), only WP and S-Pass quotas for individual companies.
And even if a space is available in the company's quota, they have to preferentially hire suitably skilled locals.
Basically, you can only get a job in Singapore if you have something that cannot be found locally. This might be niche skills for the better educated (university degree and several years applicable work experience) or the willingness to to tedious, dirty or construction jobs that Singaporeans don't like.

Thanks very much Surya2k ,hope there's no one has the quotas opportunity or is not totally  found in Singapore?

Thanks Beppi, whats the sushi skilled jobs and what of those who hold  BA degree in Arabic language,department of general section,can they have opportunity to get Spass in any jobs sector or in their course field only?

Sushi chefs are generally employed from Japan, Korea, Taiwan or China. It is unlikely that (if your avatar shows you) a black person can find such a job.
A degree in Arabic certainly is a skill that not many locals have. But I don't see much demand either. You could try at Arab countries' embassies, Arab companies' local offices, importers/exporters dealing with Arabia, or Malay Madrasahs (although they'd also require religious knowledge and Malay language skills).

Thanks Beppi your reply was so attractive thanks very much.