Plagtracker is quite effective but you need to remember to remove the document after you have checked it through this free software. If you forget to remove it and then upload your document on Turnitin or Safe Assign - it will show up as 100% plagiarism.
Effective detection of plagiarism requires primarily the current and complete database of scientific texts in a given field. That's why it's hard to talk about the program, but rather about the (web) service. There are several such services, but most of them are paid (see, for example, https://www.crossref.org/fees/#similarity-check-fees). Gathering full texts of scientific articles (and not just searching the resources of the Internet) must generate costs, so effective detection of plagiarisms can not be costless too.