If you count arbitrary transition tables, then you get a count of 63403380965376 [1].

If you count transition tables in which states are reachable and canonically ordered, then you get a count of 632700 * 4^10 = 663434035200 [2]. These machines can behave differently on arbitrary tape contents.

TNF further reduces these counts by examining machine behaviour when starting on an empty tape.

[1] https://oeis.org/A052200

[2] https://oeis.org/A107668