As far I can see SEO Auto Linker is/was the only plug-in that will do this task quickly.
For my site it will work perfectly for certain words, but other words will break the site completely making it devoid of all text and content.
The words that break it for me are 'diet','external' and 'causes'.
Of course, if it only works some of the time it renders itself useless.
I really hope the dev can find out what the problem is with this and restore it to it's fully operational state.
I'll keep my fingers crossed, because this plug-in was a nugget.
I will just mention, I have spent half a day tinkering with it, trying different settings, etc, even making a second using a URL I know is working via the plug-in, but all to no avail.
Unhappy bunny here :-(