12 gas 11 pool, 13 gas 12 pool, 12 pool 14 gas, 12 pool 16 gas, 14 pool 14 gas 14 gas, 14 gas 14 pool, 16 gas 16 pool, 16 pool 16 gas, just to name a few, each one RADICALLY different from any other.
Basically there is a spectrum of pool and gas timings for a spectrum of timings when lings first pop & when speed finishes, each one with a spectrum of commitment levels. For example, 12 pool 11 gas is a slow ling baneling allin and highly committed while 16 pool 16 gas allows for a decent timed natural while having a much faster scout denial (for fast third or fast lair followups), while 14 gas 14 pool is a middle of the road build that can be anything from a hard speedling baneling allin to a light pressure and expand build.
12 pool 11 gas aims to counter a protoss who doesn’t probe scout. You wait for his first adept to leave and you walk banelings into his main.
12 gas 11 pool is the same but with zergling speed, which allows for quicker reinforcements on large maps and a better ability to catch the first adept.
Both these hit before the first oracle pops.
14 gas 14 pool is an extreme hard counter to all forms of Protoss 1 base aggression, such as proxies or cannon rushes. It can also be a hard ling bane allin, a 2 base fast lair, or a fast third. The baneling allin variety can be held by a fast oracle since it is slower. Best vs adept, dt or robo openers.
14 pool 14 gas 14 gas is a 1 base ravager allin. Basically it kills Protoss who forge expand and who don’t probe scout (rare), cannon rushes or proxy gates. VS a typical macro Protoss it sucks since making stalkers off 2 gates or rushing a void off a stargate is plenty to stop it in its tracks. Making a robo, immortal then warp prism also hard counters it.
13 gas 12 pool is either a slow ling baneling allin or a speedling expand. You get lings out significantly slower than a 12 pool but the zergling speed can catch players off guard. So when the Protoss has a second zealot and gets more pushy you can surprise him, kill his zealots and bust his entire wall down while expanding on the back of it. This will beat lower skill Protoss who can’t recognize the timing difference of when the lings arrive.
I could go on for days, and these are just basic 1 base zerg openers.
Etc etc.