Per my research (and I may be wrong here), 19 tornadoes during one event ties this for 2nd all-time since 1950, in terms of the biggest Ohio tornado outbreak, by number of tornadoes:
1. Sunday July 12, 1992 - 29 Ohio tornadoes. (that's A LOT but unlike all the other events on this list, it doesn't ring a bell AT ALL. Not sure what the triggers were for this event. There were a couple of F3 twisters).
2. Evening of May 27, 2019 into morning of May 28, 2019 - 19 Ohio tornadoes.
2. Sunday November 10, 2002 (Van Wert F4 day) - 19 Ohio tornadoes.
Some other historic Buckeye state events:
4. Sunday April 11, 1965 (Palm Sunday) had 11 Ohio tornadoes but they killed 60. Highest in terms of death count.
5. April 23, 1968 (Wheelersburg F5) had 6 Ohio tornadoes.
6. Tuesday April 3, 1974 (Super Outbreak, Sayler Park and Xenia F5s) had 14 Ohio tornadoes.
7. Friday May 31, 1985 (Northeast Ohio, Niles-Wheatland F5) had 11 Ohio tornadoes.
8. Friday April 9, 1999 (Blue Ash F4) had 5 Ohio tornadoes.
9. Saturday night June 5, 2010 into Sunday Morning (Toledo area-Millbury F4) had 5 Ohio tornadoes.
10. Friday March 2, 2012 (the strongest tornadoes stayed JUST south and west of Cincinnati - though one F3 did clip Moscow, southeast of Cincinnati) had 7 Ohio tornadoes.