Yes, there is a limit. I've found the info here:
Can I put endless names on these lists?
No. In order to prevent abuse there needs to be a limit for each list, which was set to 3000 characters. This should allow you to add around 100 names to each list.
My source was Tibia Royal but this fansite is inactive and the links no longer work.
Question Revival V contestMarch 17, 2024
Interview with Solkrin - lead of the Customer Support team at CipSoftDecember 20, 2023
Become a TibiaQA Supporter!May 09, 2023