Are there antibiotics for all bacteria somewhere in the earth?
The number of antibiotics that remain undiscovered is huge, but is estimated to be tens of thousands of compounds. 

The number of bacteria that remain undiscovered is also huge, but is estimated to be perhaps millions of species.

Resistance to antibiotics is developed by bacteria in response to other bacteria and human antibiotic use, but in theory all antibiotics should work on previously unexposed bacteria. In practice there are resistance mechanisms that operate on whole classes of antibiotics at once(drug exporters, for instance). So there might be a bacterium that happens to be actively or passively resistant to every antibiotic on the planet, but it's a question of statistics. I think it's pretty unlikely but there are a lot of bacteria, so it's theoretically possible. (It wouldn't be a dangerous pathogen, that amount of drug-resistance genes would 'weigh down' the genome and make it slow to divide, and all those transporters would be great immune system targets. The human immune system would eat it for breakfast.)

What is true is for every bacteria, there are at least some antibiotics it's already resistant to. Furthermore, some antibiotics aren't useful because they aren't selective enough and they are simply poisons. (We use them for chemotherapy agents sometimes, but they're not useful antibiotics). 

Some fun examples: Vancomycin-resistant S. aureus is completely immune to nearly every antibiotic, including the last line of defense(methicillin) and the toxic really really last line of defense (vancomycin). It's susceptible to trimethoprim-sulfamethoxazole, one of the oldest antibiotics out there(~80 years old). On the other hand, the organism that causes tularemia is naturally immune to trimethoprim-sulfamethoxazole and always has been. It, in turn, is susceptible to nearly all other antibiotics.