Irans missiles are mostly reverse engineered and modded scud and other type russian missiles, Israel and saudi arabia are within range and the number of missiles could wipe out everything on the surface of israel(israel actually is prepared for such scenarios hence they keep many bunkers and much of their gear underground) and saudi arabia being a much larger country can still expect massive damage from that number of missiles.
Actually, Iran has a great many of a large selection of missiles.
Mostly what they are known for are ones like the Qiam 1, a domestic variation of the SCUD-C, with a range of around 750 km. Or the Shahab 3, with a range of around 2,000 km.
But some of their most numerous missiles are actually not ballistic missiles at all (other than their artillery missiles like their Katyusha clones), but cruise missiles. Like their Soumar, a domestically made clone of the Soviet Kh-55. That has a range of around 2,500 km, with a 400 kg warhead.
And since the straight line distances are around 1,500 km, any missiles fired at Israel are going to be detected and responded to as if they were fired at Saudi Arabia, Qatar, Jordan, and every other nation between Iran and Israel. In the modern era, one does not simply lob missiles against one country over another without repercussions.
And the quantity of these missiles is actually remarkably low. They are believed to have only around 25 of the Qiam missile. And at most only around 100 Shahab 3 missiles (and 50 launchers). And less than 200 (most likely around 100) of the Soumar cruise missile.
Actually, very few Iranian missiles can reach Israel, the vast majority are only capable of reaching 750 km or less (most only have a range of around 500 km). This is why Saudi Arabia, Qatar, UAE, and Kuwait have spent the last 20 years improving their own air defense capability.
And most of the warheads of those missiles are in the range of 400kg or less. Not even close to "wiping out everything on the surface of Israel", even by Spanish Civil War standards, let alone late WWII or modern standards. Odds are at worst it would only piss them off, not unlike when Saddam was launching SCUDs at them in 1990-1991.
Oh, and they also will take missile designs from anybody and make their own version. Their choice for ground attack missiles have been Soviet designs simply because that was what they got their hands on, and the Soviets still make and sell them. If they could have gotten ahold of plans and launchers for the old US PERSHING system, they likely would have made those also.
The Shahab line started because during the Iran-Iraq War they bought SCUD copies from Libya, Syria, and North Korea. The Misagh is a copy of the Chinese QW-1. The Sayyad 2 is based on the US RIM-66 SM1. The Mersad is actually a copy of the US HAWK missile. The Toophan is a US TOW copy, the Noor is a Chinese Silkworm copy, and they also have a range of missiles copied from France, Germany, and the UK.
But in most of these cases, it is not the missile that was the hardest thing to get or copy, it was the launcher. Most of their missiles are based on old Soviet designs, simply because they were able to purchase complete systems including launcher, RADAR, and command and control vehicles. They still use and make modern updates of the HAWK system, because that is the system they had when the Revolution happened.
One rumor I saw a few years ago involved Iran offering a bounty for any US equipment captured from Iran during the insurgency. Specifically the PATRIOT system, or at other equipment ranging from M1 tanks and M2 Bradleys, to any other missiles but specifically launching systems.
That seems to be their biggest problem, is in acquiring such equipment that is newer than the late Cold War era. Since they can no longer freely trade with North Korea, their missiles are being updated, but their launching systems are becoming increasingly antiquated.