The leading among them are Mumbai-terror attack mastermind Hafiz Saeed-led banned Jamat-ud Dawah's candidates who are fighting with an aim to make Pakistan a "citadel of Islam".
Sunday's attack targeted the vehicle of Ikramullah Gandapur, a candidate of the Pakistan Tehreek-e-Insaf (PTI), or Pakistan Justice Movement, after he was leaving a political meeting, two police officials told Reuters.
The Pakistan Peoples Party of Bilawal Bhutto Zardari - son of murdered premier Benazir Bhutto - could become kingmaker by forming a coalition with one of its rivals. The PPP could emerge as a coalition kingmaker if no party wins a majority, as many expect.
According to the Election Commission, about 3,675 candidates are in the race for 272 National Assembly seats and about 8,895 for 577 general seats of the four provincial assemblies.
Analysts say Khan, a famous former cricket player, enjoys the backing of military, which has ruled Pakistan directly and indirectly for most of its 71-year history.
As Pakistan gears up for election day on July 25, Pakistani celebrities have thrown their weight behind cricketer-turned-politician Imran Khan and his message of "Naya Pakistan" (New Pakistan).
'Not thrilled' with interest rate hikes
Presidents have historically avoided criticizing the Fed, which is created to be independent from political interference. China filed a challenge against the latest round of USA tariffs with the World Trade Organization this earlier week.
Khan has banked on gains in the PML-N stronghold of Punjab, Pakistan's most-populous province that has 141 elected seats, for his path to victory, successfully courting many so-called "electables" - entrenched local power brokers who often hold sway over about a quarter of Punjab's seats. The remaining 10 seats are reserved for minorities in the country.
Taking on the Sharif family, he said, "When I was a child; the USA dollar was 5 (Pakistani) rupees".
Mushahid Hussain Sayed, a PML-N senator, said the party had delivered on promises to reduce electricity shortages and improve infrastructure.
The nation has been on edge over Wednesday's elections that will decide Pakistan's new prime minister after a string of similar suicide bombings this month against political candidates. Nevertheless, the party is a strong contender in the elections and has an even stronger candidate in Shahbaz Sharif to cause an upset.
Respondents listed top two election issues as access to clean water and gas for cooking, each at 17 per cent. Inflation and corruption were ranked last, at 1 per cent each.