The “Find broken links” tool here is one of the better ones I’ve seen and they have some other stuff.
Also this tool, back in the day I used to make good money off pay per click using keyword lists I made with thousands of keywords and combinations of them.
I basically had my list of keywords in a text file, then I’d use search and replace to add another word to the keyword/phrase like this tool does.
Then I’d bid the lowest possible amount on them all, no more than 5 cents a click. I could usually pull $4k of commissions off $1k invested in clicks. Took me like 3 days to setup and I made good money off of it for like 3 years.