First of all I'll talk about the people, as far as we know, who have signed the toad contract and what they're able to do. The first person we ever see in combat with the toads is Jiraiya the Gallant. One day he performed the summoning jutsu without having signed a contract and he was taken to the home of the summoning he is meant for. He then signed the toad contract and spent a long time with the toads at Mount Myobokuzan undergoing training to learn how to harness natural energy and unlock sage mode. We only know that Minato has signed the toad contract, we don't know if he has sage mode and he most likely does not. Finally, Naruto was the last person so far to sign the toad contract so far. He trained periodically with the toads over the three year training course but they always came to him. Not until he was taken to Mount Myobokuzan in order to follow in the foot steps of his sensei and Godfather.
The canon toads that are tied to the contract are Fukasaku, Shima, Gamabunta, Gamaken, Gamahiro, Gamatatsu and Gamakichi. Then in our RP Pervy had his elemental toads added to the contract not too long ago.
An ability that I've talked about already is sage mode which is a special power of sorts that is tied to the toad contract. I'll go into detail because I am bothered and I CAN xD. Toads teach this ability to humans who they deem worthy to learn the art. It is the ability to harness the natural energy that flows all around everyone but no one knows it's there because they are not in tune with nature. In order to unlock sage mode you have to become one with nature by meditating and staying completely still for long periods of time. Then there's frog kata, I know about that but I feel I'd be straying from the point too much by going into that.
You sign your name in blood on the contract and then but your finger prints above your signature.
Bullet Point summary below if you're not bothered to read xD:
- Jiraiya, Minato and Naruto have signed the toad contract.
- The toads homeland is Mount Myobokuzan.
- Jiraiya partially mastered Sage Mode but not fully, he was never able to do it on his own. He has always needed to fuse with Fukasaku and Shima.
- Naruto fully mastered Sage Mode and uses the shadow clone technique.
- Fukasaku, Shima, Gamabunta, Gamaken, Gamahiro, Gamatatsu and Gamakichi are all tied to the toad contract.
- Sage Mode is the ability to harness natural energy.
- Sign the contract in blood and put your finger prints above your signature.