What are the Terran and Zerg equivalents of 4warpgate?

The short answer is: No. 4 Gate is a powerful strategy with a lot of flexibility. This is because, as a race, Protoss is really dependent on their Tier 1 units. Since Protoss Tier 1 tend to be fairly tough units and a cheap caster, they can get away with this.

By comparison Terran Strategies are usually based around one of three different openings:

• 3 Rax
• Mech
• 1:1:1

Each of which has its advantages. In terms of flexibility the 1:1:1 build gives you access to a wide arsenal of Terran units, but lacks the the synergy of upgrades, and thus relies on unit composition to make up. Meanwhile, Mech has very little flexbility and relies on the strength of Siege Tanks supported by Thor/Hellion to deal with Air/Melee. By comparison the 3 Rax has nice flexibility. I think this is the closest thing you're going to find to a 4 Gate equivalent.

The standard 3 Rax opening is: 2 Techlabs + 1 Reactor and producing 2 Marauder/2 Marine. Some of the nice tweaks to this are: Including Ghosts (great against Muta/Toss), Mass Reapers (powerful vs early game Zerg, with a transition into pure Marauder), Supporting with Siege Tanks (deals with most ground strategies), and even drops via Medivacs (powerful harassment and nice synergy with Stim).

By comparison, Zerg doesn't really have a nice normal build like these, though Roach/Hydra play is still fairly standard. Some people will say this is because Zerg adapt very quickly (all their unit production is shared), where as other might suggest that Zerg tech VERY slowly, and thus are forced to depend on their Tier appropriate units while trying to tech up.

I hope this helps.

Regarding the Zerg side of things, like tzenes said their isn't really a truly flexibile build for the race.

Zerg is very much reactionary, all the way to the first few minutes of the game. Your flexibility comes in with your ability to tech switch and/or adapt to your opponent's build and unit composition. In other words, if I see you 2 gating, I am going to get zerglings (with speed) quickly and spine crawlers so I would one base for awhile to hold you off, and then either counter attack or keep tabs on you to see what comes next.

Obviously when that has been determined, I can adjust my units to counter yours. Here is a great video on how a zerg player can counter a 4 gate by HDStarcraft. This showcases what the Zerg can do and how it is flexibile.

Zerg play quite differently than the other races so it is difficult to say "go this build and you'll be set for almost anything!". I recommened tzenes link in the comment to your question for a compilation of common Zerg builds with short descriptors on what they are used for/against.