My choice would be:
Scrapebox: The Swiss Army Knife of SEO (does a lot more than most other tools combined)
FCS Networker/Turbo 2.0: Tier 1 Web 2.0
GSA SER: Tier 2, 3 etc.
GSA CB: Cheapest and Automated Captcha Solver
Kontent Machine: Creating Tier 2,3 content
FolowLiker: For increasing social profiles
Some might not be directly software but still useful or needed for SEO:
Some Spinner: SpinRewriter/WordAI/TBS/some other spinner as per choice
Some proxies: Again personal choice and lot of providers to choose from
Expired Domains/PBN: Either do the hard work yourself or just buy from somewhere
Expired Web 2.0: Weebly, Tumblr etc. can be purchased for dirt cheap at Fiverr
Death by Captcha/Decaptcher: For difficult/manual captcha breaking
Some Rank Tracker: Again as per your choice
Xrumer (optional) : Many have moved away from it but still like it for forum blasts
That should be almost all you need. But you keep on finding and testing new stuff and software all the time. So, be open and test things with time.
Important: Cut your coat according to your cloth. Do not just jump in and invest money up, down and center. Plan your investments properly. Out of every 1000 guys/gals entering the SEO world, hardly a dozen or two make it to the long term. So, do not jump to conclusions of becoming rich overnight. If it would have been so easy, most of us who have been in the industry for 8-10 years would have been billionaires by now. Before investing too much, get some of the work done by paying cheap on Fiverr etc. But remember one thing as a thumb rule for Fiverr. If it is too good to be true, it probably is especially for services. People would sell Scrapebox blasts as Google Panda/Panda Penguin passed or probably at times even as Matt Cutts recommended. Understand SEO properly and what steps work at what tier. Almost every tool/service has its place but only at a definite tier. As a rule, Tier 1 links should be limited ones and from higher quality ones. Tier 2 and Tier 3 can progressively have both more links as well as lesser quality links (bulk links). And if you really worried about your money site, do not blast links to it. "Build" links gradually to your money site and "blast links" for the lower tiers.