I know Ramone Leenders was working on one, but I don't have any idea of the status.
You could ask him.
https://www.concrete5.org/profile/-/157255/...

5.7 sort of has a basic redirect system already, through the 'Location' sidebar panel.
You can put in extra urls there and it will redirect back to the main url for the page.
(I found that I couldn't put trailing slashes in the urls last time I tried it, so what out for that)

Beyond that, I think that 301s are perhaps best handled at the htaccess level. There are quite a few generators out there that will generate the rules you need, that you can then cut and paste in.

Not saying that it's not handy to have add-ons that do this sort of stuff, but I'm saying that you don't necessarily need add-ons to achieve this.

I've got an add-on that I haven't done much testing on yet that I'm planning on adding to the marketplace soon. I'd be willing to let you have a copy if you're willing to provide some feedback.

Modeled it on the Shopify method so there is a dedicated page in the Dashboard to add them. I'd be happy to have a couple of people test it out. I have tested enoguh to know it won't cause any permanent damage and you can manually remove any changes in the htaccess file if anything goes wrong.

PM for a copy if you'd like to try it out.

I'm currently working on another redirect add-on with some extra features that I need for a site.
Hope to have it finished soon.

And indeed, there are already some redirect add-ons on the market.