Многое можно сказать...
Много чего можно сказать...

Olga, I'm having a hard time thinking of a situation where one says "there's much to say." In most cases, we would say "there's SO much to say." Is that what you meant? If not, could you give an example of what you mean?

I'm not sure what is correct :)
For example, you haven't seen your friend in ages, you have much news, but you don't want to text it. So, you write 'There's (so) much to say, but I want to tell you this in person'.
Maybe, it's just missing word, we in Russian have similiar construction, and I just want to know good variant for "our listen". Honestly, I don't know how to say it correct in English.

Aha, in that case, you say “I have so much to tell you, but I want to do it in person.”

Thank you, I'll keep it in mind :)

Happy New Year, Olya!)))

Only now saw it, Happy New Year too :)

*I just now saw this/I’m just seeing this now. 😉