Yes, other than TKTS or the TDF membership, here are some of my bookmarked sites:
Everything You Need to Know to Enter Every Broadway | Show Score
https://www.theatermania.com/shows/new-york-city-theater/broadway?offer=discount
and where some of us (mostly @librarylady! ) have been lucky to win the lottery for reduced price tickets:
https://www.luckyseat.com/
I got 2 Kinky Boots tickets for about half price. Although someone in our box seat section said that she went to the box office and asked for the cheapest seats for that night, and she only paid about $10 more than I did. It was not a sold-out Friday night.
and the "Friday Forty on TodayTix" - only for Harry Potter and the Cursed Child double set - $40 for 2 shows. (again LL won a set!).
Have heard of some others...
Hope you will share!
Best Regards,
Ron Carter