You can also Take "Gray Hat SEO", do what like Google tell you do, just like. such as in different IPs, Browser, Whois ,server to create different websites in used domains in higher UR and DR. ( has not been confirmed, for all need to be avoid google detect, similar to Black Hat, If you want to use SEO Strategy, Need to use Lalicat Browser, I have used this tool for launched 7 websites, get some high keywords rank already.
You can use such as ahref tool and others as above mates mentioned. and used domains purchased way also can be searched online.