In past Pakistan cricket was dominated by Lahore and Karachi. However, in Imran captaincy especially in late 80s and early 90s he started to bring players from various clubs e.g. Waqar and Aaqib, Zakir Khan. That opened ways for players like Asif, Younis, Arshad Khan, Yasir Hameed. Hopefully now Pakistan cricket is getting out of regional grip, though still alot of influence from senior players in selecting players, so still majority is from karachi is Lahore.
There are many talented players from Quetta and they are playing good cricket in domestic circles but so far no voice in PCB for them, so hard to make into team. Lets hope we get new marshal law administrator from Baluchistan or India take back Punjab so we may get to see few players from Baluchistan.