We do have important most-used seq2seq models like T5 and Bart in Tensorflow
https://huggingface.co/transformers/model_doc/t5.html#tft5forconditionalgeneration
https://huggingface.co/transformers/model_doc/bart.html#tfbartforconditionalgeneration
https://huggingface.co/transformers/model_doc/led.html#tfledmodel