T5 comes in different sizes:

google-t5/t5-small

google-t5/t5-base

google-t5/t5-large

google-t5/t5-3b

google-t5/t5-11b.

Based on the original T5 model, Google has released some follow-up works:

T5v1.1: T5v1.1 is an improved version of T5 with some architectural tweaks, and is pre-trained on C4 only without
  mixing in the supervised tasks. Refer to the documentation of T5v1.1 which can be found here.