I think that they are both correct. The difference between then is the difference between present perfect and past.
To everyone that has come through for me, thank you
Present perfect. "Has" is not redundant at all because this form implies always to have + participle. This form is used - according to Cambridge Dictionary - to refer to events in the past but which connect to the present. People that has come through for you during a period of time until today.
To everyone that came through for me, thank you
Past. It references an specific moment in the past. People that came through for you just one time, one special day, only during 2017, ... but that may not help or support you today.