A Bomber/Ground Attack aircraft is designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching torpedoes, or deploying air-launched cruise missiles. 
During WWII with engine power as a major limitation, combined with the desire for accuracy and other operational factors, bomber designs tended to be tailored to specific roles.

However, in during the Cold War bombers were the only means of carrying nuclear weapons to enemy targets, and held the role of deterrence. With the advent of guided air-to-air missiles, bombers needed to avoid interception. High-speed and high-altitude flying became a means of evading detection and attack.

With the advent of ICBM’s the role of the bomber was brought to a more tactical focus in close air support roles, and a focus on stealth technology for strategic bombers.

Since the 1960s, only two dedicated attack aircraft designs have been widely introduced, the American Fairchild Republic A-10 Thunderbolt II and Soviet/Russian Sukhoi Su-25 Frogfoot. One anomaly belonging to this class is the Lockheed AC-130, which features as its primary armament high-caliber artillery guns adapted for aircraft use including the 105 mm M102 howitzer.

Attack helicopters also have overtaken many remaining roles that could only be carried out at lower altitudes.

Also, a variety of light attack aircraft has been introduced in the post-World War II era, usually based on adapted trainers or other light fixed-wing aircraft. These have been used in counter-insurgency operations. 

Ling-Temco-Vought (LTV) A-7E “Corsair II”

Douglas A-26C “Invader”

Martin B-26B “Marauder” 

Douglas A-4A “Skyhawk”

North American F-100D “Super Sabre”

Republic F-105B “Thunderchief”

Republic F-84F “Thunderstreak”