I did a search for you on BenchSci and found several good candidates that have been published in paraffin-embedded IHC. You can review the published data directly on the platform. Please see screenshot below:
The best antibodies to use for TNFalpha in IHC (paraffin embedded tissues) are available from Abcam (Anti-TNF alpha antibody (ab6671)). You can find the Abs description here
The Abs are rabbit polyclonal, but they were used a lot and cited in more than 100 papers. I have attached a paper that described the method using ab6671 in 2016. Abcam antibodies are quite good. Abcam people can help to solve problems if you write them and ask. In case if antibodies do not work, they might send you ( I do not guarantee this!) some other samples to try. Good luck with staining!