The previous post gave an excellent rundown of the Maycomb citizens who supported Tom Robinson during his trial in To Kill a Mockingbird. One supporter not mentioned was "one of the Cunninghams." (It could have been Walter Cunningham Sr., but he is never specifically identified.) In Chapter 23, when Atticus is speaking with Jem about the trial, he tells his son that there was one juror who "took considerable wearing down--in the beginning, he was rarin' for an outright acquittal." Jem was amazed to hear that it was "one of our Old Sarum friends." It was this man who held out for hours against the other jurors before giving in to the inevitable.
Another implied supporter was Miss Maudie herself. She reminds Jem that there were others beside Atticus who helped Tom along the way. No doubt Maudie--as well as Jem and Scout (and possibly even Aunt Alexandra)--was behind Atticus in his staunch defense of the obviously innocent Robinson.
Judge Taylor made the choice to appoint Atticus to the case, usually the other defense attorney in town received the cases like this one.
Heck Tate helped by realizing while he was on the stand that the marks Mayella had when he first saw her were not marks that Tom Robinson could have given with a crippled arm. At that point of elucidation, Heck asked Atticus while Atticus was questioning him if he could describe the nature of her injuries. This was something Atticus hadn't planned for and it helped the defense.
Link Deas interrupts the trial and shouts out in front of everyone what a good moral and steady employee Tom has been. This is not legal for him to do. He put himself in harm's way by saying what he said. Futhermore, he offers Helen a job after Tom goes to prison.
Atticus Finch obviously helped him by defending him with all him intellect in the trial.
The Negro community collected an additional offering to support the Robinson family and they gave a great offering to Atticus Finch showing their appreciation for his effort.